When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
A. The Stock LT5 Fuel Pressure Regulator.
The Stock LT5 Fuel Pressure Regulator Diaphragm is often corroded and when it fails it will leak gasoline into the Plenum through the Vacuum Port on the Fuel Pressure Regulator. It is the Corrosion within the Stock FPR that would cause Injector Failures as that corrosion is beyond the Fuel Filter.
B. The Improved LT5 Fuel Pressure Regulator (IFPR).
Jagdpanzer (Phil) has designed an Improved Fuel Pressure Regulator using an unmodified Delphi FP10016 Fuel pressure Regulator installed in the LT5 Modified Fuel Pressure Regulator Housing. The Delphi FP10016 is rated at 49 psi. Delphi FP10021 is rated at 56 psi and Delphi 10023 is rated at 43 psi. Both Delphi FP10021 and Delphi FP10023 appear identical in physical characteristics to Delphi PH10016. Any one of the three Delphi would be compatible with the Modified LT5 Fuel Pressure Regulator Housing. The Delphi can be installed or removed using a 2.5 mm Allen once the Fuel Pressure Regulator has been modified without removing the Plenum.
The Delphi FP10016 Fuel Pressure Regulator
The Delphi FP10016 is NOT modified in this Application......
there are five items that come with the Delphi FP10016
(Plastic Adapter, Screen and snap ring with two
additional sliders) that Phil does NOT use.
1. Initial Fuel Pressure Tests of Stock Fuel Pressure Regulator (SFPR). With Engine On at Idle (850 rpm).
Engine idled at 850 rpm with Fuel Pressure Reading 42 psi.
Use a bit of white grease on all the "O" rings
to make it easy to slip the Fuel pipes into the Fuel Rails and FPR Modified Housing. There are 9 "O" rings and six screws required.
The IFPR Delphi vacuum port can be rotated 360 degrees. The Allen Head screws can be loosened and the Unmodified Delphi Fuel Pressure Regulator rotated either direction within the Modified LT5 Fuel Pressure Regulator Housing. .
For this application the Delphi can be rotated so the nipple touches the Allen Wrench which allows tightening of that Allen Screw after the Delphi is rotated counter clockwise (Left Photo). The Rubber Connector can be connected on the nipple as there is clearance between the Rubber Connector and the Allen Head Screw (Right Photo).
The Vacuum Connection Nipple on the Delphi FP10016 actually slopes upward which makes it easier to connect the Rubber Vacuum Connection to the IFPR.
4. Initial Fuel Pressure Tests of IFPR.
A. With Engine On at Idle (850 rpm) vacuum line connected to IFPR.
Engine idled at 850 rpm with Fuel Pressure Reading 40 psi (Left photo). B. Engine Idled at 850 rpm with Vacuum line to IFPR disconnected
Fuel Pressure Reading is 52 psi (Right photo).
No Leaks......
5. Fuel Pressure Accelerating and on Cruise. (Engine in Full Power Setting for all tests) A 1995 ZR-1 with Stock FPR and
a 1990 with IFPR were tested with identical results.
No issues........no stumbling in any gear and very smooth in cruise. A. Cruising in 1st-5th at speeds up to 60mph resulted in Fuel Pressure of 42 psi except when decelerating pressure dropped to 38 psi.
B. Accelerating in all speeds resulted in Fuel Pressure increasing smoothly to 48 psi while accelerating only then the pressure backed down to 42 psi. C. At FULL Throttle the Fuel Pressure spiked at 52 psi in all gears. D.Cruising at 80 mph in 6th gear resulted in Fuel Pressure stabilized at 43 psi just a tad above idle pressure of 42 psi.
This is identical to what BlackZR1 experienced while testing Fuel Pressure while Driving.
Originally Posted by BlackZR1
With the extension hose and pressure gage on the dash I went for a drive. I expected that as fuel demand goes up there would be step change in pressure when the secondary pump came on. Instead, what I saw was that at idle the pressure sat at 42 psi and as I stepped on the gas pedal regardless of engine or car speed the pressure would rise smoothly and proportionate to the gas pedal. Pressure rises to 52psi by the time the pedal was about ½ way down. Any momentary or sustained WOT resulted in a 52psi pressure. So all is good.
Short roundtrip to Fresno (100 miles).....No issues and no stumbling in any gear and very smooth in cruise. Getting 27mpg - 28mpg in sixth gear going 70mph which was identical to mileage using Stock Unmodified FPR which indicates the IFPR behaves exactly like a Stock FPR that BlackZR1 Tested While Driving with various Throttle Positions.
6. Quarter Mile run to determine IFPR performance under WOT conditions.
Over 100 mph with soft shifts with No Stumbling. Identical to Quarter Mile Results with Stock Fuel Pressure Regulator.
7. Overall Observations of performance of the IFPR during Initial Testing.
The IFPR using the Delphi FP10016 is identical to the Stock FPR in terms of Fuel Pressure. The IFPR Installation requires the removal of the Plenum and removal of the Fuel Rails. Have Jerry's New Fuel Rail/Fuel Pressure Regulator "O" rings on hand as good time to replace Fuel "O" rings. Also have on hand 2 Plenum gaskets. The FP10016 performed perfectly under all driving conditions (1/4 mile, cruise, Hot, Cold, idle).
8. Long Term Test of IFPR.
I see no issues for long term use as I have now tested two IFPR with over 300 operating miles. It will now be so easy to change out Delphi FPR removing failed Delphi (may never fail once installed) or change out the Dephi (for higher pressure or lower pressure Dephi) from the Modified Stock FPR Housing which take only a couple minutes (release fuel pressure in Fuel Rails first). I have installed one Prototype IFPR and two Production IFPR with the same results.....NO LEAKS and PERFECT Performance under ALL Driving Conditions.
I have been driving every day and even a 100 mile trip.....
Perfect all the way.....NO ISSUES..... The IFPR was also tested on a 1995 ZR-1 with no issues.
Installation was identical and operational characteristics were identical.
9. Summary
The IFPR (with Delphi FP10016) performed perfectly with identical Fuel Pressure of the Stock FPR (The IFPR behaves exactly like the Stock FPR while Driving. The Stock FPR Housing is the only item modified with Stock Delphi FP10016 unmodified for adaptation of the Delphi FPR. The Production IFPR installed was adjusted by loosening the Allen Head screws and rotating the Stock Delphi for perfect alignment of the vacuum port making it easy to attach the vacuum line. The IFPR will work on 1990 - 1995 ZR-1s with identical installation methods and operational capability.
I have run into a couple Stock FPR that have failed. The Stock FPR are almost impossible to find and very expensive. Changing a Stock FPR out on the road will be almost impossible. With the IFPR changing out a failed FPR on the road will be a 5 minute job albeit the Delphi will likely NOT fail for a long time.
There does exist several Delphi FPR with different Pressure Ratings and it would be easy to change out a Dephi with a different pressure rating. The Delphi FP10016 is identical to the Stock FPR in terms of Fuel Pressure. Delphi FP10016 is rated at 49 psi. Delphi FP10021 is rated at 56 psi and Delphi 10023 is rated at 43 psi. Both Delphi FP10021 and Delphi FP10023 appear identical in physical characteristics to Delphi PH10016. Any one of the three Delphi would be compatible with the Modified LT5 Fuel Pressure Regulator Housing.
Pulling the Plenum for most is a BIG deal and most often the Plenum is Pulled to install New Injectors or to fix a No Start Situation or an Alternator. I would say if you install New Injectors or recondition your Starter or install a reconditioned Alternator...then also install the Improved Fuel Pressure Regulator at the same time.
Changing Out Improved Fuel Pressure Regulator (IFPR)
The Improved Fuel Pressure Regulator (IFPR)
The Delphi installed in the Improved Fuel Pressure Regulator Housing (Designed and
Fabricated by Jagdpanzer (Phil)) can be changed out in a couple minutes on the road.
One of Several Delphi can be installed with the Delphi FP10016 being identical to the Stock
LT5 Fuel Pressure Regulator in Performance.
The Delphi FP10021 can also be used in the Modified Fuel Pressure Regulator Housing. (Delphi FP10016 on left and Delphi FP10021 on right)
Both FP10016 and FP10021 having identical physical characteristics.
1. Changing Out the Delphi FP10016 Fuel Pressure Regulator requires a 2.5 mm Allen Wrench.
First relieve the Fuel Pressure in the Fuel Rail by loosing the Fuel Lines wrapped with a paper towel from the Fuel Rails
(release the Fuel Tank Pressure by removing the Fuel Cap). When Installing Delphi FP10016 the Vacuum nipple should just touch
the Allen Wrench shown below.
2.Disconnect the Vacuum Line and remove the six Allen Head Screws and the Retainer Ring.
(Best to loosen the six Allen Head Screws and lift the screws with washers out with the Retainer Ring).
Remove the Delphi FP10016 leaving the Lower Seat Washer in place.
3. The Removed Parts in the Change out of the Delphi FP10016.
4. Install the New Delphi FP10016 with the Blue "O" Ring, Black "O" Ring Washer, Black "O" Ring. Make sure the Seat washer is installed in the IFPR Housing
(Seat Washer not installed in Photo).
5. Install the Retainer Ring with Allen Head Screws and Washers installed in the Retainer Ring. (be careful not to tip the Screws out as you insert the Retainer Ring over the Vacuum Nipple).
Install the Vacuum Connector.
I see no issues for long term use as I have now tested three IFPR (2-1990 and 1-1995) with over 300 operating miles. It will now be so easy to change out Delphi FPR removing failed Delphi (may never fail once installed) or change out the Dephi (for higher pressure or lower pressure Dephi) from the Modified Stock FPR Housing which take only a couple minutes (release fuel pressure in Fuel Rails first). I have installed one Prototype IFPR and two Production IFPR with the same results.....NO LEAKS and PERFECT Performance under ALL Driving Conditions.
The Delphi FP10016 is NOT modified in this Application......there are five items that come with the Delphi FP10016 (Plastic Adapter, Screen and snap ring with two additional sliders) that Phil does NOT use.
Phil has eliminated the plastic ring, the screen and the snap ring and is using the "O" rings.
Pulling the Plenum for most is a BIG deal and most often the Plenum is Pulled to fix a No Start Situation, an Alternator or to replace Injectors. I would say if you recondition your Starter and/or install a reconditioned Alternator or New Injectors...
then also install the Improved Fuel Pressure Regulator at the same time
New Secondary Port Throttle Vacuum System for 1990-1995.
1. Installed New Secondary Port Throttle Vacuum System for 93'-95' (easily modified for 90'-92'). Now have zero vacuum leaks on three 90's, and one 95' ZR-1(One 91' has secondary vacuum system removed).
This is an absolute Must Do if you Really are serious about reconditioning the
Secondary Port Vacuum System (the original Rubber Connectors are Hard and Deteriorated).
2. New Secondary Port Throttle Vacuum System for 1990-1995.
This complete NEW vacuum system designed for the 93'-95' can be installed on a 1990-1995 ZR-1. For 1990-1992 this can be accomplished by substituting the longer Manifold Differential Pressure vacuum line on the original 1990-1992 ZR-1 Vacuum System for the shorter curled MDP Vacuum line in the New 93'-95' Secondary Port Throttle Vacuum System.
The New vacuum system connectors are New soft rubber and easy to disconnect connectors which are very tight (just twist the plastic tube back and forth and they will let loose). The Original hard rubber connectors are impossible to disconnect without cutting the connector lengthwise (with razor blade) to remove the plastic tube.
3. Modifications (re-arrangement of connectors) of the New Secondary Vacuum System to fit 1990-1992.
A. The Tee (T) was moved and a 1 inch long 1/8" Fuel Line PCV/EEC (SAE 30R7 obtained at O'Reillys) was used as a splice where the T was located. The T was installed for the Drivers Side Secondary Canister which is identical to the Stock
B. The Stock 1990 Manifold Differential Pressure (MDP) Vacuum Line was used and added to the New Secondary Vacuum System. I replaced the stock L fitting on the 1990 MDP was replaced with the New L fitting removed when T was re-installed for the Drivers Side Secondary Canister which is identical to the Stock 1990 Secondary Vacuum System configuration.
C. In this case I also used the Stock line with New L fitting from the check valve to the Vacuum Pump line as that Stock line was just a bit longer
New 1993-95 ZR-1 LT5 Corvette/Stock 90-92...........Modification of 1993-95 ZR-1 LT5 Corvette
Secondary Actuator Vacuum Control Lines.................Secondary Actuator Vacuum Control Lines (90-92)
New 1993-95 ZR-1 LT5 Corvette Secondary ...............Modified 1993-95 ZR-1 LT5 Corvette Secondary
Actuator Vacuum Control Lines..................................Actuator Vacuum Control Lines (90-92)
Went for a test drive with the 1990 and ALL is perfect
4. New Secondary Vacuum System Availability.
These New Secondary Vacuum Systems for 93'-95 which can easily be modified for 1990-1992s are offered on Ebay for $100 but one can buy them with an offer for less
The Ultima 124 Amp Alternator - Remanufactured R111799A from O'Reillys fits the 1990 ZR-1 perfectly. This Alternator costs $100.The Ultima is a bit heavier with the body a bit larger in diameter with identical mounting points as the stock Alternator. The Ultima 124 Amp Alternator fits perfectly under the Plenum of the LT5.
I have taken this #72 ZR-1 with Phil's Improved Fuel Pressure Regulator and the Rebuilt Ultima 124 Amp Alternator on several Quarter Mile Runs and one 100 mile round trip with NO ISSUES. I have yet had to replace any Rebuilt Alternators from O'Reillys
Both the bottom and top Alternator Mountings and the threaded hole at rear of Alternator that excepts the bolt from the small angled brace that attaches to the Injector Housing Bolt are ALL identical to the stock Alternator. The Hot wire can be seen just above the rear mounting bolt and is actually better positioned on this Ultima 124 amp alternator than the stock alternator.
1. Installing All Aluminum Alternator Pulley.
The Installation of original or New Billet Aluminum Pulley is very easy with my 15/16 inch modified Combination Wrench and 5/16 inch Allen Wrench. SeeAll Aluminum Alternator Pulley
2. Minor Modification of Air Horn.
The smaller single vacuum port (nipple) on the Air Horn pointing back under TB on 90' (90' only) is for vapor Canister Control and which vacuum line is connected to the Charcoal Vapor Canister control valve under the Drivers Side Headlight (on the 90'). This single Vapor Canister Control vacuum nipple almost touches the Ultima 124 Amp Alternator body and has to be bent just a bit as shown in the second photo. This assures the Alternator is not touching the rubber vacuum connector that fits on the vacuum nipple of the Air Horn.
Cooler Thermostats, Thermostat Modifications, Engine RPM, and Fans
Cooler Thermostats, Thermostat Modifications, Engine RPM, and Fans
Here is what I have found regarding LT5 Stant Thermostats.
1. You want to run the engine at coolant Temperatures of 180 deg as the design requirement...……...Running cooler Thermostats only lowers coolant temperatures when running coolant below 180 deg F (which is too cold for the LT5 engine). Once the 180 deg Thermostat and 160 deg Thermostat are fully open at 180 deg, Coolant flow is the same through each Thermostat with equal cooling as directly dependent on coolant flow.
2. Drilling Holes in Thermostats offers minimal (non effective) additional Coolant Flow...….A 1/8 inch diameter hole in the flange will only offer additional flow area of .0123 square inches. Which one such hole will increase the total flow area by .016 or 1.6% (three 1/8 inch diameter holes would increase the flow area by 4.7%). This thinking does not address the change in coefficient of Discharge of such small holes. The Stants tested would be fully open with a flow area of approximately .785 square inches at 185 deg F.
3. The Stant Thermostat Opens a bit less with age......…...Marc suggests a 15% deterioration in Full opening area of the Thermostat over time as the Thermostat ages.
4. The LT5 Water Pump Flow is proportional to Engine RPM. ......The LT5 Water Pump Flow rate is insufficient at RPMs less than 2,000 RPM for adequate Coolant flow at the higher Ambient Temperatures. Larger Aluminum Radiators DO compensate for inadequate Coolant Flow at low RPMs. Fans Turning on at 205 deg F do help considerably. And KEEP The Radiator, Oil Cooler, AC Condenser CLEAN.
5. Fan Air Flow is inadequate when the ZR-1 is not moving...…..This was noticed when the ZR-1 coolant decreased in Temperature when shifting from 6th to 5th at 65 mph (going from 1,500 to 2,200 rpm) but while not moving increasing the rpm from 750 to 2,000 had the opposite effect actually increasing coolant temperature .
And I was thinking the issue was solved wherein it is TWO issues (Fan air flow at low speeds and water pump coolant flow at low rpms).
In regard to Item #2 and #3 above...…..Compared to the normal aging of the thermostat of 15% over several years of use one would be much better off installing a NEW Stant Thermostat gaining 15% flow area as compared to drilling three 1/8 inch holes in an older Stant Thermostat only gaining 4.7% flow area.
I replaced my Steel Water Pump Pulley with a Billet Aluminum Water Pump Pulley. The Billet Aluminum Water Pump Pulley does not have the ridge (larger diameter) on the front.
Place New Serpentine Belt on all pulleys except the water pump pulley.
Compress Belt Tensioner with hand so you can insert a stick of wood (1" x 2" x 24").....
or long handle 1/2" drive breaker bar to hold Belt Tensioner compressed.
Slide smooth backside of Serpentine Belt on Billet Aluminum Water Pump Pulley
(easy since it has no ridge on front edge of Billet Aluminum Water Pump Pulley).
Remove stick of wood or 1/2" drive breaker bar.
This applies to LT5s and L98s.
Now I know why I got the Billet Aliuminum Water Pump Pulley :p
LT5 Billet Aluminum Water Pump Pulley.....L98 Billet Aluminum Water Pump Pulley
L98 with Air Pump Eliminated Note the Power Steering Pulley rides on smooth back side of Serpentine Belt on L98
Pump cavitation in an impeller is the result of a drop in pressure of a moving liquid through the impeller's eye. This reduced pressure causes bubbles to form, as the pressure of the liquid continues to fluctuate and drop, the bubbles collapse. This starts at around 5,000 rpm and would actually reduce the increase in coolant flow and resulting radiator pressure buildup. Which increase in radiator pressure is too much for the seals on each end of stock radiator. The problem is the inherent 7,000 rpm capability of the LT5 and having a water pump that is a bit low on gpm at 2,000 rpm while a bit too much flow at 7,000 rpm (ignoring the effects of cavitation for a moment).
Now having said that, I would expect the various aluminum radiators to not have this inherent weakness not having the same end seals as the stock radiator. Further, the flow characteristics would be different for each radiator (head loss, coolant paths, and heat transfer).
As Per Marc Haibeck graph provided to the ZR-1 Net email list by Graham Behan about ten years ago, the Coolant Pump flow rate through the engine (not the radiator or thermostat) is:
15 gpm at 800 rpm
18 gpm at 1,000 rpm,
44 gpm at 2,000 rpm,
65 gpm at 3,000 rpm,
90 gpm at 4.000 rpm,
120 gpm at 5,000 rpm at which time cavitation is starting.
We do not know water pump flow after cavitation starts and we do not know head loss of coolant flow through various radiators. We do not know current pump flow through stock radiator as the test above was pump flow through engine only.
I have not seen the design pressure characteristics of Aluminum Radiators listed and would assume which pressure is greatest at the top and reduced by head loss as coolant is forced through radiator.
This whole discussion is a bit complicated by a water pump that does not function well on either end of the rpm range of the engine and a radiator with an inherent weakness because GM did not want a unique radiator for the circumstances ��
Instead GM settled on a most unique thermostat housing and thermostat to solve the high coolant temperature issues (Warm Climates) associated with high engine rpm and the radiator pressure using a conventional water pump impeller which works for most of us. That is except for HOT desert climates and traffic (we then go to Aluminum multi core radiators keeping rpms above 2,000 rpm in traffic) :p
Some guys have even modified fan function for higher air flow rate which definitely will help coolant high temperature issues in traffic :thumbsup:
If we determine that our multi core aluminum radiators will take the pressure we still have the cavitating water pump as a secondary issue.
First....Drain Coolant from system and remove Air Cleaner, Air Cleaner Housing. A. Removed Oil Cooler Adapter from Oil Cooler. B. Removed three 10 mm bolts bottom Fan Housing. C. Disconnect the two fans electrical. D. Remove two 10 mm nuts and one 13 mm bolt on Passenger Side. E. Remove one 10 mm nut and one 13 mm bolt on Drivers Side. F. Remove two 10 mm horizontal bolts on Drivers side. G. Remove two 10 mm horizontal bolts on Drivers side holding ??? to Drivers side of Radiator Shroud. H. Disconnect Temp Sensor bottom of Shroud. I. Remove five 10 mm bolts top Fan Housing. J. Remove three 7 mm bolts left and right bottom side of Shroud. K. Disconnect Vent coolant overflow hose top Passenger Side. L. Lift Drivers Side Shroud clear of Hood Hindge. L. Lift Passenger Side Shroud bending the lower tab up and around AC lines. M. Lift and remove Fans. N. Disconnect Top Radiator Hose. O. Remove three 13mm bolts from Thermostat Housing (More Coolant will drain from the system). P. Loosen short radiator Hose between Thermostat Housing and Radiator (Twist). Q. Remove Thermostat and remove Thermostat Housing Half that was connected to Radiator. R. Lift and remove Radiator. S. Clean Oil Cooler, AC Condenser, and bottom of Radiator Housing.
The worst place to have mice is under the Plenum and specifically......
under the starter or in front of starter.
Mice get in this area usually from on top of bell Housing in from the rear of the Coils.
The Mice then bring in all sorts of trash as well as pee in this area.
I have been using Bounce sheets in between the Plenum Runners and on each side of Fuel Pump Regulator which has controlled the Mice issue so far but I have been searching for a better method. I am going one step further after I found some mice had moved my older Bounce under the starter of an LT5
Z51JEFF mentioned the use of Cayenne pepper which seems to be a great method I am now experimenting with.
Using Cayenne Pepper rather than Bounce (Bounce has to be removed each time I fire up the LT5) seems like a more permanent and probably more effective solution.
I have figured out a very effective method to place Cayenne pepper under the starter and in the area Mice enter under the Plenum from on top of the bell Housing. The Method involves the use of a plastic straw.
1. First I poke the empty straw in to Cayenne Pepper and as can be seen the Cayenne stays in the straw to the depth of insertion which is perfect amount of Cayenne Pepper to place on each side of starter.
2. I insert the straw with Cayenne Pepper gently (the Cayenne Pepper will stay in straw as long as you do not hit the straw abruptly) down between the Fuel Regulator pipes (once on each side of the Fuel Regulator).
3. Once straw is between the starter and Injector Shields I jar or blow into the straw and Cayenne Pepper ends up exactly where it is needed in and around the starter.
I also place a bit of Cayenne Pepper on the panel below the Left and Right Headlight (in front of coolant overflow for example) which are other places mice like to camp out.
Oh.......It appears I can easily remove Cayenne Pepper from any area with an air hose
Locating Relays Above Drivers Side Footwell (1990 #72)
There exist 4 relays (two each side of steering column).
Shown below is the yellow Air Bag connector which was hanging loose.
To gain access I removed the lower Hush Panel screwed to the Front Support Panel with 7 screws with 7mm hex heads
(disconnecting the courtesy light and the ALDL connector). The Hush Panel also had one 10mm nut next to the
fire wall that had to be removed.
I then removed the Front Support Panel to which the hush panel was attached (two bolts on left side
with 13 mm hex heads and two bolts on right side with 10mm hex heads).
The two Relays and flasher are shown on left side and hanging relays and Air Bag Connector shown on right side.
Each pair of Relays are slip locked together before sliding towards rear of car in the Fixed Bracket into a locked position.
The hanging courtesy light connector and ALDL hanging is also shown which are both connected last to the
Hush Panel before it is installed.
The Relays are shown (below) disconnected (left photograph) from the Fixed bracket and then connected to the Fixed Bracket
(right photograph) on the left side of steering column.
The Fixed Bracket has tabs to which the Relays are attached by inserting on Fixed Bracket and sliding toward rear of car.
The Fixed Brackets appear very difficult to remove and the Fixed Bracket in the left photograph (below) with broken tabs
was left in place (right side of steering column).
A Fixed Bracket I had with tabs (1990 corvette L98) was JB welded to the smooth face of the Fixed Bracket with broken tabs
facing opposite of Fixed Bracket left of steering column.
The two Relays on the right side of steering wheel were then inserted on the Fixed Bracket (backwards) and
locked in place as normal. The Air Bag Connector was connected under the counsel up and out of the way.
The courtesy light connector is shown hanging down on left side and ALDL is hanging down on right side.
Both are connected to the Hush Panel installed last.
The Clutch Safety Switch Bypass can be seen (Connector with a U-shaped yellow wire inserted) to
lower left of steering column (also....next thread #293).
The two Relays can be seen on the upper right side in photo above installed facing to the front of car
and the two Relays upper left side in photo above installed facing to rear of car next to Flasher.
The Front Support Panel is now installed (two bolts left (13mm heads) and two bolts right (10mm heads)).
The Hush Panel is then installed (7 screws (7mm heads) and one 12mm nut near fire wall
after connecting the courtesy light connector and ALDL connector.
Just bypassed my Clutch Safety Switch on 90' #3032 and 91'
I made extra Bypasses (3 inch 12 gauge yellow connector Bypass) for my other 90's.
I left the original Clutch Safety Switch in place.
The Electrical Bypass (3" pre-soldered connector) can be installed in 10 min by removing the front two, side two,
and bottom three Hush Panel screws (7mm hex head) as well as the nut from bolt holding Hush Panel up on the Fire
Wall (Drivers Side).
The Hush Panel Light has to be unplugged once the Hush Panel is loose.
The Clutch Safety Switch Connector is easily identified with the two larger gauge wires (yellow and purple).
The yellow wire controlled by the key switch and the purple wire to the Starter Solenoid (or in my case the
added Starter Relay installed under the ECM).
The Clutch Safety Switch connector can be easily separated with one locking tab release. The end of the connector
with the yellow and purple wires has two electrical tabs included as shown. The other end of the connector
going to the Clutch Safety Switch can be tucked away under the steering wheel.
The 3 inch 12 gauge yellow connector Bypass can be connected to the existing tabs within the connector
without any electrical tape required since the connectors are very well insulated within the connector
and very tight. The Connector with the Bypass can then be tucked upward above the Hush Panel and the Hush Panel
placed back into position and secured by the seven screws (7mm hex heads) and the Fire Wall nut and washer.
You now have a Start condition without the requirement to depress the Clutch as long as Transmission
is in Neutral. You can depress the Clutch to make sure you do not lurch forward just in case the transmission
was left in a gear.
You also now have eliminated one of the NO START issues associated with the Clutch Safety Switch.
The original Clutch Safety Switch is left as installed with no issues.
Many of us are much more familiar with standard transmissions not having a Clutch Safety Switch
You can actually install this Clutch Safety Switch Bypass on the road if you have the 3" Electrical Bypass
made up as a spare and a 7mm socket (1/4 inch socket wrench)
With several posts recently discussing Camshaft wear on associated mating surfaces (Head and Cam Cover)......here is a new aberration to think about
This is a low miles (less than 30K) stock 90 Head.
The tips of all the cam lobes (8) on one intake camshaft (the other camshafts have a perfect wear pattern) of one head are shown here. Can this be explained in terms of cause and effect?
The two photos are taken on drivers side Head with front of engine toward the right.
The Cam Wear on the tips can be seen on the Cams pictured below.
The lifters related to this camshaft seem to have a normal wear pattern.
Technical History
Originally Posted by Marc Haibeck
I first saw a lobe with that wear pattern about ten years ago. The worst thing about it is that the lobe is actually pitted or maybe chipped on the high end of the tip. Since then after having the cam covers off of maybe 100 engines I have seen it about two additional times. We put those cams back in service long ago and there has been no repercussion. I would not be too concerned about it.
My theory as to what is happening. I wonder if the lifter is lofting and then smacking back down on the lobe. If that is the case, excessively long time with engine speeds over 6000 rpm or a weak valve spring could promote the problem.
What is the maximum cam pressure on the lifter for an LT5 engine?
Going from a 4,000 rpm to over a 7,000 rpm engine is a BIG factor in Cam Pressure and wear.
I also know from an experience that the cam tips are not parallel with the Lifter surface on the LT5 engine. (Cam Tip being the high "edge" of the Cam that gives the Lifter maximum compression).
The localized pressure on the lifter must be very difficult to determine in that case....
I assume the cam tip being tilted and off center on the Lifter surface keeps the lifter rotating. The lifter rotating under the cam acts like a rolling intersection (not purely frictional). The surface of the Lifter is moving vertically and horizontally as the Cam Tip slides/rolls across the Lifter. (It is hard to imagine this happening up to 60 times a second).
I happen to have 1990 ZR-1 #3032 (1G1YZ23J4L5803032) the last 1990 ZR-1 sold to public
1 is USA....
G is General Motors....
1 is Chevrolet....
YZ is Corvette ZR-1.....
2 is 2 door hatchback...
3 is Manual Belt Restraint system...
J is LT5.....
4 is check digit...
L is 1990.......
5 is Bowling Green.....
803032 is (3032) number off assembly line......
For you that cannot get rid of the Red INFL REST (1990) on the panel....here is a Clue where to start........inside the car
INFL REST Connectors inside car.
There are a Left and Right Yellow INFL REST Connector inside the car that can accumulate resistance over time.
(Left - just in front of Drivers side Speaker at the level of the top of the Speaker under carpet) Easy to get to by just pulling back the carpet a bit in front of speaker (not the speaker carpet).
(Right - Just to right of center hump front foot rest under carpet)
Depending if you have Code 16 (Drivers side) or Code 26 (Passenger side) locate the Left or Right Yellow Connector.
(3 inches long and 3/8 inch diameter three pin) Disconnect and Reconnect Yellow Connector to regain continuity.
I have had two 1990s that re-grounding of the Sensor under Battery (Left) and Under Window Washer (Right) did NOT solve the issue of the INFL REST.
REMEMBER.......To Clear INFL REST Codes you GROUND A to K in the ALDL Connector, Turn Key ON, When INFL REST flashes release GROUND for 3 seconds, Re-GROUND for 3 seconds, Release Ground, Turn Key OFF.
To make it SIMPLE......to Re-Ground Sensors Under Hood.
Drivers Side....Remove Gill Plate, Battery, Battery Platform.
Passenger Side......Remove Gill Plate, Left (looking at wheel) Wheel Well Shield, Remove Windshield Water Bottle.
You need a 1/4 Inch Socket Wrench, 1/4 inch drive 13 mm socket, 1/4 inch drive 10 mm socket and that special 1/4 inch drive Swivel 10mm socket.
To remove the Gill Plate Drivers side and Passenger Side....10mm open end and 10mm socket and two 1/4 inch drive Torx 30 and Torx 15.
To shine up the frame rail surface and the sensor bottom you use a small drill and wire brush as shown.
Those underlined items are "Links".
Same in my signature.....those items are links.
Left click on links and it will take you there.
Now if you have IPhone.......click on the item and then select "more" and click on "Web View".
Then in Web View you just touch the item on the screen and it will take you there.
One top fuel dragster 500 cubic inch Hemi engine makes more horsepower than the first 4 rows of stock cars at the Daytona 500.
It takes just 15/100ths (0.15) of a second for all 6,000+ horsepower (some believe 8,000 HP is more realistic - there are no dynomometers capable of measuring) of an NHRA Top Fuel dragster engine to reach the rear wheels.
Under full throttle, a dragster engine consumes 1-1/2 gallons of nitro methane per second; a fully loaded 747 consumes jet fuel at the same rate with 25% less energy being produced.
A stock Dodge Hemi V8 engine cannot produce enough power to drive the dragster's supercharger.
With 3,000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into a near-solid form before ignition.
Cylinders run on the verge of hydraulic lock at full throttle.
At the stoichiometric (stoichiometry: methodology and technology by which quantities of reactants and products in chemical reactions are determined) 1.7:1 air/fuel mixture of nitro methane, the flame front temperature measures 7,050 deg F. (Oxy-acetylene on "cut" is 6,300)
Nitro methane burns yellow. The spectacular white flame seen above the stacks at night is raw burning hydrogen, dissociated from atmospheric water vapor by the searing exhaust gases.
Dual magnetos supply 44 amps to each spark plug. This is the output of an arc welder in each cylinder.
Spark plug electrodes are totally consumed during one pass. After halfway, the engine is dieseling from compression, plus the glow of exhaust valves at 1,400 deg F. The engine can only be shut down by cutting the fuel flow.
If spark momentarily fails early in the run, unburned nitro builds up in the affected cylinders and then explodes with sufficient force to blow cylinder heads off the block in pieces or split the block in half.
In order to exceed 300 mph in 4.5 seconds, dragsters must accelerate an average of over 4G's. In order to reach 200 mph well before half-track, the launch acceleration approaches 8G's.
Dragsters reach over 300 miles per hour before you have completed reading this sentence.
Top fuel engines turn approximately 540 revolutions from light to light! Including the burnout, the engine must only survive 900 revolutions under load.
The redline is actually quite high at 9,500 rpm.
Assuming all the equipment is paid off, the crew worked for free, and for once NOTHING BLOWS UP, each run costs an estimate $1,000.00 per second.
The current top fuel dragster elapsed time record is 4.428 seconds for the quarter mile (11/12/06, Tony Schumacher, at Pomona , CA ). The top speed record is 336.15 mph as measured over the last 66' of the run (05/25/05 Tony Schumacher, at Hebron , OH ).
Putting all of this into perspective:
You are driving the average $140,000 Lingenfelter 'twin-turbo' powered Corvette Z06. Over a mile up the road, a top fuel dragster is staged and ready to launch down a quarter mile strip as you pass. You have the advantage of a flying start. You run the 'Vette hard up through the gears and blast across the starting line and pass the dragster at an honest 200 mph. The 'tree' goes green for both of you at that instant.
The dragster launches and starts after you. You keep your foot down hard, but you hear an incredibly brutal whine that sears your eardrums and within 3 seconds, the dragster catches and passes you. He beats you to the finish line, a quarter mile away from where you just passed him.
Think about it, from a standing start, the dragster had spotted you 200 mph and not only caught, but nearly blasted you off the road when he passed you within a mere 1,320 foot long race course.
01-15-2018, 07:02 PM
The Improved LT5 Fuel Pressure Regulator
