patrick sieben

I need some help. I spared little cost and wanted it looking original. I built a 383 with JE pistons, gapless rings, edelbrock 6087 port matched heads. Compression ratio 10.5:1. Large intake, large runners, 52 mm TB, Crane compucam 2032 (according to crane the best cam for computer meeting smog (500 ppm CO).
Cam Specifications:
Degrees Duration @ .050 Int./Exh.
214 220
Degrees Advertised Duration Int./Exh.
270 276
Degree Lobe Separation
112
Open/Close @.050" Cam Lift
Int./Exh..
0 34
47 (7)
Int./Exh. Gross Lift Int./Exh
.452
.465

1.5 roller alu rockers. The plenum was hogged out and port matched. There is no restriction through my air filter. It dynod just as good with or without filter. I set the timing so it just detonates. Fuel pressure is at around 50 psi at it's best. The MAF was gutted. FAST chips made a chip for me with my #24 FMS injectors. I have a performance DUI distributor. The engine dynod 290 SAE HP RWHP which remained fairly constant from 4000 to 4800 rpm. No sense in going further than 5300 rpm the torque took a dive. Torque was an immense 550 NM (380 ft-lbs). WHat am I doing wrong. With this setup I was expecting 360 RWHP. The crank will take 538HP. Oh I forget it is a full 3"exhaust with long headers from TPIS. And a random cat converter. I ran 8.6 seconds on the 1/8 with vigilante 2600. I know some guys out there are making the power with the same setup or a lesser setup. Where would you guys think it is at. Iknow everyone is going to aim at the cam with the 1.5 rockers. But still with a 383 I should be making more power than that. So guys where do I start?

ELEVENS

Patrick,

I've seen this sort of thing a few times, and watching my friends go through it, it is maddening. It certainly sounds like you have checked and rechecked all the "simple things" like timing A/F, etc.

Guys I know that had this problem:

1) The guy "lived" with low HP for years after many complaints to the engine builder fell on deaf ears. When the engine needed a refresh, it was discovered that the wrong pistons were used, resulting in rediculously low CR. Upon further investigation, the shop owner finally confessed it was a dusgruntled employee's last day at the shop that assembled the motor, and malicious intent became obvious.

2) bad cam lobe

I think a compression check might uncover the problem in both of these cases, maybe give that a try. I hope you get is sorted out, and be sure to report back here with your findings. Best of luck - Bill

patrick sieben

I have checked all cylinders by means of the limp cylinder method. unplugging one cylinder at a time and watching rpm drop with a seperate tach. all are creating same power. I have also checked exhaust manifold temp. all tubes with infrared thermometer and all are close in temp.

I have done a CR test by using clay to see how much cc is above piston a tdc and found it to be 10.5:1 as my engine builder has promised.

Keep it coming guys.

atotalnincompoop

did you piece this configuration together yourself?

I followed a build up from a book, so that i could use the experience of veteran engine builders, in the past I had tried to figure out my own cam, head, piston, etc. conbination and it rarely ran how I thought it would. maybe your cam isn't a good match for your setup, good luck :cheers:

Ramanstud

maybe ignition? spark, gap, coil, module, etc? Doesn't sound like you actually have problems with it, but hell you're shooting in the dark anyway; right?

I assume you port matched your gaskets to that hi-flow setup? I didn't. :jester

You may just be limited by the lengths of those runners. Are they siamesed at all? Perhaps a SR would help that baby breathe a little more.

Just some thoughts...


[Modified by Ramanstud, 11:01 AM 6/8/2003]

patrick sieben

Due to the fact that I thought it would be ignition I had dui get me a brand new one. Got a new clear cap, got a new rotor and have changed wires three times over. The plugs are all brand new and gapped according to dui specs. They are bosch platinum. No arcing in the dark and the wires are spaced as should be. I don't expect to find say 60 horses there anyway. The runners are not siamesed but are the larger accel ones. I wanted the engine looking stock from the outside. I made a mistake on the torque calculation i'm actually making 407 ft-lbs. I found a caring making comparable powwer over at thirdgen. Close to the same setup.

Yes I picked the parts myself, also based on all kinds of info from people around advising what is smart. Crane advised me on the cam. I chose the 1.5 rockers because I chickened out on the piston to valve clearance. I didn't do the measurement and was afraid to just us the 1.6 because everyone does. I almost got the edelbrock large base but they couldn't supply. It ended up being accels base. Yes I portmatched all the gaskets. The port matching was done the way it should, not just taking the material off everywhere but only there where the air would encounter an obstacle.

Keep it coming guys :)

Beach Bum

Patrick,

From your set-up, I honestly don't think you have anything wrong... you could probably find another 10-15 rwhp through tuning, and I believe your random cat is costing you somewhere around 15 rwhp, other than that, doesn't look like you're losing a lot of hp anywhere else.

You have a lazy cam lobe, that coupled with its harder to make HP with long tube runners. As another note, your computer program is more than likely wrong in its prediction of that is the most aggressive cam lobe you can run and still pass emissions. I have run cam's way more agressive than yours in the past on a TPI motor and still easily passed the very tough California emissions testing.

As a note, your current HP level of 290 rwhp combined with good 60 fts is capable of solid mid 12's at somewhere around 108 mph in a C4. Consider going to a more agressive cam and also consider a different intake system, and I believe you might see the type of HP you're looking for.

good luck
Beach Bum

patrick sieben

Beach man,

I always enjoy reading your replies and respect them as many others on the forum. You have eased my mind a bit on what I need to expect and thank you for that. I guess what you are telling me is that I'm running out of options if I want the motor to remain stock looking. I love the chromed runner tubes. Ok so another 10 to 15 if I get rid of the cat. I assume you are telling me to run a straight 3" tube or a gutted cat. Didn't think it would do so much. I selected random because of it's high flow capability.

As far as the chip. I know you have been very busy with chips and tuning. My diacom however runs weird. I do get data but with glitches. Which has me thinking the values aren't always right. This is due to the fact that diacom claims errors where my ecm doesn't.

I had the chip done by Ed wright. I just can't find the time to deepen myself into chips. I gave him all data. Including the fact that I wanted to get rid of the 9th injector. I does still start very rich though but as long as I leave it be and warm up a little it doesn't stall.

The guy at the dyno did tell me I was running a bit lean, but he only had an infrared exhaust analyser built by bosch which has a response time of no better than 15 sec. So I set the fuel pressure at about 55 psi and I did gain HP. (290)

I don't understand what you mean exacly with the chip. I know the cam is mild.

Funny thing is that you haven't advised to do the 1.6 rockers is that because what I said or because you feel it doesn't do anything.

What cam do you think I shoud run?

Keep it coming guys :)

Hole-Shot

I don't follow what you mean here. What obstacles are you referring to? Rough casting or re-shaping the entire port?
:cheers:

Beach Bum

Patrick,

Thank you for the kind words.

In regards to your desire to want to stay with the stock long tube runner, then consider the ASM runners if you are already not running them.... as a casual observation, I have noticed the majority of long tube runnered motors that run strong on the track and dyno seem to be running them.... however, I don't know why. Considering you could sell your existing runners for around $ 200 and the new runners cost somewhere around $ 300, would only be a $ 100 investment plus a few hours of elbow grease, thus even if there is no improvement, you weren't hurt too bad.

In my opinion and personal testing a Single cat design, regardless of its a Random or not significantly hurts a modified motor. A random is good for around 5-7 rwhp vs a stock cat, and removal completely is in the area of 15 rwhp and maybe even a couple more with your 383. However, I think cars equipped with a dual cat design, the HP loss is very little... if any. Therefore consider wedging a couple of randoms in the tunnel....I've heard it can be done, but never actually seen it. If you wish to remove the cat, get a gutted cat and to comply with clean air, simply change the cat at the dragstrip... will only take 10 minutes or so at the track with the right tools.

Your cam is a lazy lobe that opens and shuts the vavle very slowly, I think 1.6's will help this a bit, probably 5-10 hp give or take a hair.

With the chip.... I actually don't play with the chip at all anymore.... exact opposite, I rarely think about it or touch it... I think fine tuning the chip is overrated unless it is wayyy out, but thats a whole other argument. As a last tip, 50 psi fuel pressure is pretty high.... I too have 24 lbs injectors, but only run right around 42 psi fuel pressure. Motors run best a little bit on the lean side.

cheers,
Beach Bum

jmr302

It's probably your setup AND a rough tune (chip needs refinement). I've run a similar setup:

383 stroker (11.2:1 CR)
Dart Iron Eagle 200cc heads
Comp Cams XE268 cam (224*/230* at .050, 110 LSA and .508"/.512" max lift with 1.6:1 roller rockers)
Accel Superram Base
Ported plenum
SLP runners
24# FMS injectors
Ported MAF
1-5/8" primary full length headers with no cats
Borla mufflers
DUI HEI
MSD 6AL
K&N airfilter

This made 319 peak hp at 4400 rpm and 423 peak ft lbs at 3500 rpm at the rear wheels. Assuming 16% drivetrain power losses that's 380 hp and 504 ft lbs at the flywheel. It was in a poor state of tune when it dyno'd too. Ran rough above 3000 rpm and the idle surged like mad. The Formato's in Florida were doing the chip tuning but I got frustrated with them. We kept swapping chips and it ran worse and worse. I'm saving up for an Accel DFI or F.A.S.T. EFI box.

Anyway I have 10* more intake duration on the cam and more lift because of the 1.6 rockers but our compression ratios are fairly close and we're both running similar intake setups. Not sure how the cylinder heads compare. My base timing was at 8 degrees and fuel pressure was about 42 psi. So your tamer setup was about 30 hp / 20 ft-lbs down on my poorly tuned setup.

I would consider cam & rocker ratio changes and really try to get a good tune out of the thing.

patrick sieben

Hole shot man,

You are right I was unclear on what I meant how I port matched. I did so not by taking material off everywhere.. When ports don't match you need to take material off both mating sides when you do it wrong. When you do it right you consider the direction air flows. The air should not flow from a small diameter then epand and then go into a smaller diameter. This will cause energy loss. POrts ar matched by only taking away the material on the receiving side. which means when air ""sees"" a flat edge. If it sees a ridge, this doesn't matter. So typically from a runner point of view you only take material off of the base. from a plenum point of view you only take material off of the runner etc.

Beach man,
You are right the cat is no effort to take off. I beleive tuning the chip is over rated too. I have a very stable idle at 700-800 rpm according to my cluster. My temperatures at the track are high at cruising on a 70° day i show 180° water. so there is little to be won there. So therefore I try to say my chip is a happy oone. By changing to 50 ish psi I got the motor to give more rwhp. So possibly that does call for a new chip. The pressure was maintained even at wot.

Thanks guys. Keep it coming



[Modified by patrick sieben, 12:03 AM 6/9/2003]

radwebster

i have no advice to offer here, as i have not yet built a motor, but i must say that this is one if the best threads i have read in a while. :yesnod:

i learned a lot from this thread already, please keep the responses coming, and i hope you get the numbers you are looking for patrick :thumbs:

patrick sieben

I was and am really happy. cause the motor ran wel as of day one. I don't have much more than 5k on it. and am running synth right now. So what is the standard for a motor like this=

FD2BLK

Patrick, your set up is a good set up with the exeption of the cam. You need a bigger cam, look at your torq numbers the reason they are high and your horse power is down is due to the cam. I agree with beach bum on this one you could go up in cam size and still pass emisions and 1.6 rockers would help with upper RPM HP numbers some what.

Vic'89

It looks like the comp cam is not strong enough, no way that cam could make 360 RWHP, like you are looking for. I ran that Cam in my Irocz and it was slow.

You could probably pickup another 20-25 rwhp, but not much more than that.

Good luck.

Vic

C4racing

Several people have touched on the torque issue but I'll second it. Especially if your rear wheel numbers are 300 hp 400 lb*ft torque (ballpark), it's easy to see that your motor is "torque biased". Long tube runners and a stock plenum have the advantage of making high torque due to increased air velocity into the cylinders. Unfortunately, at high rpm long runners can't fill the cylinders as fast (with the same volume as shorter runners). I know, I had a smiliar setup with a 383, ASM runners, ported plenum and base, but only 9.7:1 CR. Similar cam but with 1.6 RR made 335 rwhp but 445 rwtq! At the engine that's 524-556 lb*ft of torque, depending on which conversion factor you use.

Regarding breathing, I don't remember anyone discussing the heads. Have they been flowed and what are their flow numbers? Might give some clues if the flow numbers are low or not balanced well intake/exhaust. Also, what are the primay tube diameters of the headers and what are the exhaust pipe sizes from header to tailpipe? Lastly, I'd pitch the cast runners and get some ASM runners. Better flow and still look stock.

My point is that for those that like stock looking hardware under their hood you'll have to live with the basic L98 advantage of huge torque potential at the expense of horsepower. But here's the real question: for what do you want to use the car? Stoplight-to-stoplight driving, autocrossing, daily driving, and short-track roadracing all favor torque over horsepower numbers. Torque is what pushes you into the back of your seat when you mash the gas pedal! :)

However, if speed is your thing then horsepower starts to become your friend. Whether at the drags or longer road race courses, anything with a reasonable straightaway wants hp, especially to overcome wind resistance (not to mention pushing our lead sleds around).

If you want to keep the stock appearance then (as others have suggested) I'd look at the cam and possibly the RR ratio. Some people like 1.6's on the intake and 1.5's on the exhaust. Also, make sure the cam was "degreed" correctly during installation.

My last comment is about the chip. Until you've seen first hand what gains are possible when you have the chip programmer do the programming while your car is on a dyno, you will probably think that mail-order chips are as good as any. Perhaps they're ok for the money (dyno time is expensive, not to mention the programmer's time) but often they leave a lot on the table performance-wise. If you have a choice opt for an eddy current type dyno over an inertial dyno (read, NO inertial Dynojets!). Inertial dynos can only tune at WOT whereas eddy current dynos can tune at idle, off idle, and part throttle. :yesnod:

For example, do you have any idea what your A/F ratio is across the entire rpm band? (the stock narrow-band O2 sensors can't measure accurately away from 14.7:1) Know what fuel trim you're asking the injectors to do? Any idea what the ms "on time" is (ie, if the injectors are too big or too small)? Do you know what the total timing advance is across the entire rpm range? Mail order chips are guesses at best because virtually none of us have the exact same combinations of components that were on the car used for the programmer's generic chip. I've seen gains in excess of 20% from the 1st guess chip to the final chip, not to mention that the 1st guess timing and fuel were sometimes WAY off.

If you've gotten anything from my rambling I hope it's that L98's inherently make torque (over hp), stock looking intake hardware is hp limiting, engine internals (cam, RR, CR, cam timing) can have a significant impact on hp, and dyno tuning of computer chips is highly under-rated (ie, there IS hp to be gained here, especially the non-detonating, non-lean burning, fuel-efficient, reliable kind of hp).

I'm not an expert on all this and I probably only know enough to be dangerous. :lol: Just my humble opinion. :seeya

89gta383

I made 300 rwhp and 380 rwtq with a 383, 9:1 comp, same crane 2032 cam, superram, edelbrock base, slp 1 3/4 headers, dual cats and 3" cat back with ed wright chip. Ed runs his chips lean, so watch the O2's. You will have to send it back to him a few times with scanner data to get it close to optimal on the tune.

I had 1.6 rockers on both sides with that cam, and would agree that it was pretty lazy on the lobes. Don't believe what you hear from Crane, they don't know everything. I passed emissions with the LPE 219 cam, and my current comp 230-236 .604-.608 lift cam, both with a cat convertor.

Put a LPE 219 cam in it and it will wake up with more tuning, porting of the runners as was suggested before, and a fuel pressure check. I had to add a fuel pump inline because my fuel pressure would drop at wot. The stock pump can't keep up sometimes. :seeya

CorvetteZ51Racer

I agree with the weak cam issue. From Crane's perspective, they are ALWAYS going to err on the side of caution when suggesting a cam for an emissions vehicle, IF you can only talk to the people who answer the main phone lines. If you have the "other" phone numbers, you get much better info :D

Anyhow, I would take a good long hard look at your fuel pressure, injector size (take a good look at the pulse width on the injector, as well as the duty cycle), etc. You would be AMAZED how much power you can lose if your AFR's are off. Prime example...we put a Winston Cup restrictor plate motor on the dyno and messed around with fuel temperatures in the bowl (which in turn affects AFRs) to simulate race conditions...we saw power changes of ~10% from being off by as little as 1 point on the AFR (i.e. running 11.7 instead of 12.7) I don't remember who said that engines run best while running a little lean, but that simply is not true when it comes to making power. You want your WOT AFR to be somewhere between 12.7 and 13.3 There is a little to be gained (like 1-2 HP) from staying on the rich side of that, but Dynojets are not repeatable enough to statistically pick up that difference, and the extra fuel savings of the slightly leaner (but not lean) AFR are preferable for me.

If I were in your shoes, I would check the following:
1) injector duty cycle and AFR at WOT
2) fuel pressure at WOT to see if the pump can keep up...that may be why you're having to crank the pressure up
3) back the timing off so it doesn't detonate...you do NOT want detonation in it
4) verify the cam timing, but given the weak cam, it's probably correct
5) you can gain something by going to the bigger rockers, but a cam change would do a lot more, and there are plenty of folks who have passed with the 219 cam (though I don't know how well it matches your head's flow)
6) you might want to check the head flow numbers to see how hard you're pushing those heads. since i'm not too familiar with the edelbrock flow numbers, I don't know how well matched that head is to your motor

Until it's time for major work on the motor again, unless you absolutely want to, I'd wait on anything involving the heads (not counting rocker arms), and just mess with the tune. A PROPER dyno tune (i.e. not an inertial DynoJet tune) is the only way you're going to get a good tune under all operating conditions. You can be dead on at WOT, and way off under part throttle.

On the Ed Wright thing, someone said he runs his chips lean....I only have hands on with one of his chips for a friend's LT1 with a top end on it, but his chip ran so pig rich that the car was only getting 10 mpg, and I was choking on the raw fuel fumes at idle.

patrick sieben

Thank You for the great responses!!!!!! :)
The cam was degreed with an offset bushing and is in there straight up.
I get a great great milage around 20 mpg.
There isnīt an eddy current dyno around here open to the public as far as I know. But What I can possbly do is get an afr meter and drive around right? Where would you guys hook one up? Do I need to do welding? While the car was on the dyno I checked fuel pressure. The stock pump remained strong and the pressure didn't drop.

On the detonation. That was really good you picked that up. The power I was initially making was 292 rwhp. I backed off timing to 289 rwhp because it was detonating some. Now it only detonated once on the dyno and never on the street.

Occasionally I go to the track and it is only 1/8 long. It is defenitly a street car and a little street. I like the torque.

On the torque issue. I need to understand one of newtons laws better. Torque is force times lever length right? Therefore if I make 400 ft-lbs at the wheels it will also be 400 at the flywheel. It is only power that can be lost by the drive train (energy). You can not lose torque. Please shoot holes in this hypotheses if you like.

What I have noticed though is that all of you seem to be happy with the numbers and the current setup. This puts me at ease. As a matter of fact it seems these are good numbers for my setup. Some one did say they were making more torque wit a similar setup. Now I can live with the fact that I built this motor for torque, because I did. But that why do others get a higher torque number. Everything suggested until now is sure to drop my turque numbers and raise my rpm.

By the way the valvetrain floats at 6200 according to cam.

I didn't flow the heads. The heads are straight out of the box from edelbrock. The combustion chamber volume is 60cc. The valves are 2.02 intake ans 1.6 exhaust. According to edelbrock these head are for engines up to 400 cid.
The heads have been designed for maximum flow with a tpi base from edelbrock. They have been cnc matched. However edelbrock could not supply the base. so I got an accel one and port matched it.

keep it coming