Hey,

I am looking to put fuel injection back into my C4 (1986) as it was removed by the previous owner for an LPG conversion. I run a mild 400 driven daily. Does anyone know the suitability of the standard TPI setup of a corvette for a 400? Do I need something with more capacity?

Thanks in advance...

Chris :rolleyes:

 

The superram has been proven to work well by a few :D :thumbs:

 

Or you could roll the dice and slap a Stealthram on there. :D

 

You've got several options:
1) Modified TPI (big base and runners). This option isn't a good one for a 406 which with its large stroke and big bore likes to breathe.
2) Accel SuperRam base and runners. This is a great choice for street mills that don't need to rev very high. Look at Jesse and Cork's times with 406 SR motors to get an indication of how they'll run. They aren't the best for max effort big motors though.
3) TPIS MiniRam. Good manifold for large motors. Has very short runners and moves the powerband up pretty high but with the 400's 3.75" stroke you can stand to kill a little bottom end. Simple manifold too but does have a few tuning issues when combined with a cam with a lot of duration (read overlap).
4) Holley StealthRam. I haven't played with one of these yet but it's essentially a tunnel-ram intake with EFI bungs and a plenum attachment. With its plenum and runner length it should be roughly between a SR and MR and should prove to be a pretty good manifold. Though I believe the factory one won't fit under a C4's hood but someone on here has built a couple plenums that will.
5) EFI converted single plane. My personal favorite. Very easy to tune, not cam sensitive and will make gobs of power. It does require some fabrication (on the manifold builder's part) to fit under a stock C4 hood but it works very well, especially on big motors.
-Jeb

 

since I RESEARCHed THIS SUBJECT! LET ME POINT OUT A FEW THINGS
(1) heres the flow numbers
(2) your MAX AIRFLOW WILL BE LIMITED TO THE MOST RESTRICTIVE OF THE TWO,(RUNNERS OR BASE INTAKE) that YOU PUT IT ON and THATS THESE FLOW NUMBERS FROM MATCHED INTAKE AND RUNNERS

Stock out of the box intake manifold with runner
Stock....................198.72 cfm
ACCEL................213.52 cfm
Extrude/ACCEL....217.11 cfm
Super Ram............220.67 cfm

the stock TPI has a hard time flowing 230cfm even with minor port work, look here
most of this info is right off the accel,holley,edelbrock, and TPIS sites, add a little math and the results become much clearer!!!
GETTING YOUR Intake....... length ....... port in -- out
Stock GM Base--- 6.375"------ 1.47"- 1.96x1.2
TPiS base------ -6.125"------ 1.75"- 2.09x1.28
Accel base----- -6.125"------ 1.75"- 2.09x1.28
Holley base------- 6” runner 2.3”- 1.9”x 1.23 (2.337 sq inches)
Runners
Stock TPI----- -- 7.250"------1.470" round(1.70 sq inchs)
SLP ----------- - 6.625"------1.600" round (2.01 sq inchs)
Accel LTR------- 6.625"------1.615" round (2.05 sq inchs)
TPiS----------- 7.625"------1.660" round (2.168 sq inchs)
Mini ram -----3.5”
LT1 ----------3”
Runners (measured individually)
Stock....................203.17 cfm
ACCEL................242.02 cfm
Extrude/ACCEL...275.83 cfm
Super Ram............289.18 cfm
Intake manifold with 3/8 inch radiused intlet
.............................222.45 cfm
Holley stealth ram ………..275cfm
Stock intake manifold with runner
Stock....................198.72 cfm
ACCEL................213.52 cfm
Extrude/ACCEL....217.11 cfm
Super Ram............220.67 cfm
Holley stealth ram …..275cfm

ACCEL Hi-Flow intake manifold with 3/8 inch
radiused inlet.........251.51 cfm
ACCEL Hi-Flow intake manifold with runner
Stock....................215.83 cfm
ACCEL................232.53 cfm
Extrude/ACCEL....243.21 cfm
Super Ram............240.24 cfm
Extrude-Honed ACCEL Hi-Flow intake
manifold with 3/8 inch radiused inlet
............................275.83 cfm
Extrude-Honed ACCEL Hi-Flow intake
manifold with ACCEL runner
............................266.94 cfm
Edelbrock Performer RPM manifold
(Stock)..................286.51 cfm
Edelbrock Victor Jr.
.............................275.24 cfm

HOLLEY STEALTH RAM
[b]the HOLLEY STEALTH RAM FLOWS at 275cfm out of the box, and has the potential when matched to the correct heads and cam to totally out flow most other intakes available,can easily reach 300cfm with minor port work and costs much less
Stock…………………………… 275cfm
Ported…………………………..300cfm
Runner lengths
Stock tpi manifold 8” runners 11.25”, cylinder head 6” total 25.25”
Accel super ram manifold 8” runners 7” cylinder head 6” total 21”
Holley stealth ram manifold 6.26” ” cylinder head 6” total 12.26”
Edelbrock performer RPM runners 6” ” cylinder head 6” total 12”
Edelbrock vic jr , runner length 5.5” ” ” cylinder head 6” total 11.5”

take the time to read the links
http://www.gmhightechperformance.com...holleystealth/

http://www.eecis.udel.edu/~davis/z28...age021105.html

GAINS OF 60hp PLUS have been reported on mildly reworked engines and Im sure on a full race style, or engine designed to use the extra air flow engine the results would be far greater

http://www.jegs.com/cgi-bin/ncommerc...19&prmenbr=361
compare that to a super ram at $1370 plus
flows about 240cfm to 275cfm with SERIOUS port work

http://www.thunderracing.com/index.c...yid=1125#P2944[/url]
HOLLEY STEALTH RAM (intake ,plenum,fuelrails, regulator)
about $460-$520 to convert your TPI plus cost of small base HEI ignition and small parts
flows 275cfm-300cfm with port work


[b] http://www.fasterdeals.com/garageindex.html]custom height stealthram to fit under corvette hoods,LINK [b]


when you look at the choices the upgrade to the HOLLEY STEALTH RAM GIVES YOU THE MOST FOR YOUR MONEY, just like a 4 barrel carb potentially out powers a 2 barrel carb on the engine years ago its the increased airflow potential of the newer EFI intakes that limits to a great extent the power your engine can make now, your ECU matches the fuel to the ENGINES AIR FLOW AND IT THE EFFECTIVELY USED AND AVAILABLE AIRFLOW THRU THE ENGINE THAT MAKES POWER

I found this info and I figured you guys might like to look it over, now the first thing I want to point out is where the DATA came from. and KEEP IN MIND ITS REAR WHEEL HP AND The TPI INTAKE IN THE TEST consists of 58mm TB, fully ported plenum, AS&M largetube runners, and highly ported Edelbrock base WHICH MEANS ITS ALREADY MAKING AT LEAST 25HP-30HP MORE THAN A STOCK TPI INTAKE)


http://www.eecis.udel.edu/~davis/z28/winter01/dyno/

The engine was basically the same,in all the test except for the intake manifold, consisting of a ZZ4 crate motor, AFR190 heads, LT4 HOT cam, and SLP 1-3/4" SS headers. Trans is a 700r4 with a Vigilante 2800 stall converter. The Engine Control Module (ECM) was a '92 TPI stock ECM (MAP/speed-density) with a modified EPROM.

I HAVE GONE TRU AND WILL PICKED OUT THE IMPORTANT POINTS TO SAVE YOU TIME IN THE CHARTs AND GRAPHS ON THE SITE

TPI engine.....283 PEAK rwhp @4800rpm peak
AVG. TQ 291.5
AVG HP 269.5

miniram
303 PEAK rwhp @6200rpm peak
AVG. TQ 285.8
AVG HP 269.1
IT LOST 29 HP at 3800 rpm and MADE 48 MORE HP THAN THE stock TPI at 6300 RPM


stealth ram
342 PEAK rwhp @6400rpm
AVG. TQ 319
AVG HP 300 it lost 28 hp at 3600 rpm BUT GAINED 66 HP AT 6600 RPM
over the PORTED AFTERMAKET HIGH FLOW TPI
342 rear wheel hp is aproximatly equal to 427 flywheel HP FROM A 350 SBC ENGINE, figuring a 20% driveline loss rate.

the use of a longer duration cam and only measureing PEAK HP would tend to benefit the miniram and STEALTH RAM intakes to a MUCH GREATER extent than the TPI, THATS HOW claims of gains of 100hp are made for some intake combos, while its TRUE that you can make in excess of a HUNDRED EXTRA hp at 6600rpms is due more to the TPI not being able to flow air (LOSSES) keep in mind that a LARGER ENGINE DISPLACEMENT WOULD BENEFIT EVEN MORE from the steathram
link to c-4 stealthram





[Modified by grumpyvette, 5:47 PM 8/19/2003]

 

:iagree:
The only differing factor I really take into account is my use of the longer/larger runner, larger plenum Super Victor when I do single plane conversions...It flows a HELLUVA lot more than a Victor Jr....
-Jeb

 

How much money would one be looking at for a single plane conversion?

 

HOLLEY OFFERS THIS INTAKE ALREADY DESIGNED FOR EFI, OR YOU CAN BUY A SUPER VIC AND HAVE IT CONVERTED,MOST PLACES CHARGE AT LEAST $350 for the conversion (JUST FUEL RAILS AND INJECTOR BUNGS)PLUS THE $200 FOR THE SUPER VIC ITSELF


Part #: 9901-101-1
Fuel Rail Kit available. Order Holley P/N 9900-172
summit price for the intake, $289.99 fuel rails,$206.99
9900-171 $647.99
total about $1150 plus shipping, linkage, trans brackets ETC, and youll need to use your old injectors and sensors and don,t forget a new air filter assembly

msd makes a somewhat similar throttle body #2250 $ 413.69

but either way its about $900-$1200 without injectors MINIMUM
which is not real bad but its more than the custom stealth ram at $775


heres what a single plane conversion looks like

throttle body =$550



HERES ANOTHER OPTION BUT BE PREPARED TO PAY $4500-$6600








[Modified by grumpyvette, 8:11 PM 8/19/2003]

 

How about a FIRST unit? Has anybody eve used one of these?
http://www.firstinjections.com/products.htm

 

I charge $1250.00 out the door for a complete bolt-on EFI single plane that will hook right up to your components including your OEM style twin bore throttle body. I fabricate an adapter elbow so you don't have to run a 4v throttle body like that pictured above. The problem with the 4v t.b.'s is that they won't fit under the hood with any type of conventionally available air cleaner assembly; I know, I run one... I fabricated a custom airbox for mine and even though it is very cool looking and works fine for the street it is very restrictive on a motor making serious power...I pick up 4-4.5 mph at the track when I pull it off!
-Jeb

 

the only problems with grumpys recomendation is there is no drag data on anything fast to compare it to air flow is nice but the final numbers come at the track and since nobody fast yet has used this stealth manifold it is still a wildcard :cheers:

 

jebs 4v conversion intake looks very promising and the edelbrock maifolds will out horse any holly manifold on the market
when you are talking manifold talk edelbrock
when you talk carb talk holly
both of these companys do very well with there specific specialties and they should keep it that way :cheers:

 

With an 86, Id definitely do the SR for an auto.
With a stick, id also look into the MR and HSR.