Clint E.

I recently installed the Holley Stealth Ram on my 88 Iroc 5.7 TPI, here is the list of mods performed on the engine:

Stock bottom end with Edelbrock 6085 Aluminum heads, SLP camshaft ( Duration @ .05 218int 224exh Lift .330int .335exh with a lobe seperation of 114deg. Gross valve lift is .495int and .502exh.), 1.5 ratio roller tip rocker arms, stock throttle body with air foil, 24lbs/hr SVO injectors, edelbrock headers, edelbrock exhaust with no cat, MSD 6AL ignition box, MSD coil, Accel wires, before the stealth ram was the original TPI with mild porting on the base and plenum, both setups (TPI and Stealth Ram) were custom tuned on a dyno. Behind the engine is a 95' T56 and a rebuilt rear end with an Eaton Posi and 3.73 gears, with the Hotchkis rear suspension package and subframe connectors.

Now heres what I cant figure out, when the car was totally stock with just the engine mods listed above with the stock 700R4 no tuning and stock rear end and suspension it ran a 13.476 @ 99.06MPH, so then I installed the T56 and at the same time did the 3.73 gears and the new suspension as mentioned above and got a custom dyno tune done to the chip, the car then ran a 13.893 @ 98.47MPH. I knew that autos ususally give better ET's but I thought that the 3.73 and custom tune would make up for it but it didn't. So I then decided that my engines powerband was not really matched to my gearing so I purchased the steallth Ram and the Car ran a 14.129 @99.03MPH.

I have checked fuel pressure and compression seems to be good sorry about the long post but this ones got me stumped.

camarojoe

You should have been faster before the Stealthram. I suspect your bottem end, but check all your sensors, all ignition and fuel components first, before you tear up your engine looking for the problem. Compression tests don't mean jack when you're looking for a ring sealing problem. You HAVE to do a leakdown test to determine your rings condition. This is the only accurate test.

Your car should have a lot higher mph even without a custom chip. GMHTP was running a similar setup on an 87 Iroc and w/ a moddified tpi setup they were running around 106mph. Then after putting the stealthram on and after some timing and fuel pressure adjs. they were running mid 12's at around 111mph. This was with the stock chip. The stealth ram was worth a solid .4 tenth and 4 mph gain, which means that intake rocks and it's not the problem.

You may also have a bunch of goofups if you're actually running slower. You may have several vacuum leaks, a couple of bad plug wires, or some silly **** like that. Other things that you can't overlook when modifying a car are things like valvetrain geometry, gasket matching all ports, making sure all your parts are clean (no dirt), etc. Stock blocks and their clearances are not perfect either. If you have a lot of miles on your engine it may be best to go through the engine and rebuild. I'd always do that when adding heads and a cam. Some people get lucky and run good with the stock short block, but I think most people would be better off by installing fresh pistons and cleaning up the bores for the rings to seal good. I hope I can help more, I know I rambeling a bit, but I'd suggest to triple check are your ecm connections, go over the timing, and check out the fuel pump. Most power losses are fuel related.

gsf-87IROC

What are you shifting it at?

evilho7810

Do you know how to drive a stick correctly? And how was the weather. My friend runs low 13's in his car all day long and when I tried it I ran a 14.5. So mabey it's your driving.

Clint E.

I am shifting between 5000 and 5500 RPM with wide open throttle shifts. I taped a fuel pressure gauge to my windsheild and tested the car at wide open throttle through the first four gears and It read 44psi the whole time, and with the engine idling with the vacum line for the AFPR disconnected it reads 45psi. Had the scan tool on the car when we did the tuning got a few weird values fro the TPS so it was replaced all other sensors looked OK MAF failed a few days later but I replaced it. The car runs excellent it just seems to be running slow. No vacum leaks and the initial timing is set at 12deg. I will post the values of the compression test when I get home. The bottom end does have 220 000kms on it I dont know what that is in miles.

TRAXION

A stealth ram with Heads and a 218 cam should be shifted in the 6500 rpm range ... not 5000-5500rpms. If the motor isn't creating any power after 5500 then something is wrong. Here's an example:

Mike Davis' Stealth Ram with AFR heads and a 218 HOT cam

You said you did tuning? With a Wide Band O2?

How is the bottom end? Have you done a leakdown test?

Tim

mrr23

for what you have, you'll need at least 4.10 gears. friend of mine with a 383 HSR and t56 went 13.60 with a 3.27 gear. everyone i know has gone quicker with 4.10 gears. the first gear in a t56 is a 2.66 the 700r4 is a 3.06 first gear. and yes shift it at 6200. that's where he started shifting his and gained e.t.

Kevin Gray

Ditto what CamaroJoe and Traxion said.

My engine combination is similar and I'm running mid 12's in 90 degree weather (shifting at 6400 / 6200). That's with 3.23s and a first gear ratio of 2.53:1 for the TH350. The problem is not the StealthRam and it's not the gears. We'll be able to help more once you run a leak down compression test.

Clint E.

Thanks for all the info so far guys!!

Here is my compression test numbers I have not done a leakdown test yet but I plan to how do you do a leak down test anyway?
The first number is with the cylinder dry and the second is with 3 drpos of 5W30 oil. Test was done with the throttle wide open.

Cyl#1-135psi-140psi
Cyl#2-135-140
Cyl#3-135-150
Cyl#5-135-150
Cyl#7-140-145
Cyl#2-145-150
Cyl#4-140-152
Cyl#6-125-145
Cyl#8-130-150

well I dont know if much can be told by these numbers but I plan to do a leakdown test soon. Could a bigger throttle body help? Thanks Again.
Clint

Clint E.

Oh yeah and I did do tuning with dyno and wide band O2 sensor.

mastrdrver

I think 3.73 are good, he really doenst need 4.10s with that cam. I would suggest shifting higher. I think if you muve your shift point to between 6000 and 6500 I think you will go faster.

DannyT

You may want to start with your timing and set it back to stock specs. It's possible you are getting spark knock and that will KILL your performance.
And with the Stealth Ram you HAVE to shift later than 5000-5500 RPMs or you WILL be slower than stock.

RedIrocZ-28

I experienced the same thing. Although I have hellacious spark knock between shifts.

How do I remedy that??

I really wish I could show you guys my problem. I get to about 5600 and then the spark knock hits and the car literallt falls on its face, the nose drops and then I am forced to shift it. When it hits 2nd, it takes off like a bat out of hell again. Strangely, though, I can ride out 2nd longer.

BTW, I logged a track run and I had 8.50* of spark retard decaying throughout 1st gear.

grumpyvette

ON EVEN ON A STOCK engine a STEALTHRAM tends to make big improvements in hp/tw BUT ALL ABOVE ABOUT 4400RPM, NATURALLY YOULL NEED TO KEEP ABOVE 4400RPM MOST OF THE TIME TO SEE THAT IMPROVEMENT
the guys are correct, you should be shifting at some rpm level above 6200rpm, and a 4.11 rear gear WILL TEND TO keep your engines rpm level higher more closely matching the steathrams flow charicteristics
the cam you chose while a good choice for a TPI is slighty mild for max performance matching the stealthrams effective rpm range, something like these hydrolic roller cams will match BETTER but will require machine work,clearanceing,and higher compression and matching tuning changes

http://dab7.cranecams.com/SpecCard/D...1=Display+Card

http://dab7.cranecams.com/SpecCard/D...1=Display+Card

Lunkan

Today, I took my car to the strip for the first time with new converter. I wasn´t that pleased with the times. My best lap was the first!?! 9.325@75.125 / 14.657@91.597. Didn´t get the 60´s below 2.114

The best time with stock converter was 9.374@75.7

My setup (L98):
- stock bottom (rebuilt)
- HSR with AFPR (tried from 41 to 51 psi)
- 991´heads from 69 (supposed to be ported, milled and 3-angle cut)
- cam Bullet Racing with stock pushrods and lifter (dur@050 220/225, lift 510/525 LS112)
- Ford Racing SVO#24
- MSD 6AL + Pro Billet distr.
- Edelbrock TES
- 3" race catalyst
- Wells MAF

TH700 with TCI Streetfighter and TransGo
- B&M TorkMaster 2400
- B&M Console Mega Shifter
- Stock 3.27 9-bolt rear

The car won´t pull enough on 3rd gear and don´t rev more than 5.700rpm. Shifting is around 5.500.

I´m running base timing @ 10deg. without knock´s and tried the ARAP chip (also with base timing corrected) but no results. It seems that the best chip is ARAP with the timing lowered a bit. I also get some exhaust detonation that I can´t get rid of. It comes whatever chip I´m using.

What could be my problem? I´m using stock suspension.

DannyT

Try retarding the base timing or increase the FP

Clint E.

Hey thanks for the Input guys I am going to get back to the track as soon as possible to try to shift higher like you all said, kinda off topic but a friend with a 93' 5.0 Mustang is selling his procharger P600? I think for $100 beacause it has a bad bearing what do you guys think I know I should probably post in the power adder board but just thought I'd ask.

Black363IROCZ

I really hope this isn't gonna turn into another lame TPI advocacy post. Stealth ram should've shed at least .3 of a second for a stock setup. perhaps that extra second you spent burning out is a result of the HSR. Get a miniram if you want even more noticeable gains

grumpyvette

"Stealth ram should've shed at least .3 of a second for a stock setup. perhaps that extra second you spent burning out is a result of the HSR. Get a miniram if you want even more noticeable gains "

HAVING RUN BOTH THE MINI RAM AND HSR on several engine combos INCLUDING MY CORVETTE, ID have to say that on every combo IVE tried, the HSR has made more torque over a wider rpm range and about the same peak hp, at least on the admittedly limited number of engine combos IVE tried and over all the HSR has proven to make the cars IVE WORKED ON FASTER,IN FACT after the last several TRACK tested combos I sold the MINI RAM I had.
now don,t get me wrong the mini ram makes very good peak hp! but PEAK HP is the WORD TO WATCH THERE!
but I do agree that you should have seen more than a .3 second gain,it looks like youll need serious help tuning the combo, READ THIS AGAIN

http://www.gmhightechperformance.com...holleystealth/

Clint E.

Well my new Compression leakdown tester is comming so I will post the results soon. I think that the poor ET's are due to a compression problem that has been getting worse, so mods show no improvement, every time i have run the car It has been roughly a year apart, and If the leakdown test looks goodI will look to the tune, keep posted.

Clint.

Clint E.

Ok I finally did my leakdown test with some interesting results here they are:
Cly#1- 79%
Cyl#2-27%
Cyl#3-65%
Cyl#4-40%
Cyl#5-35%
Cyl#6-50%
Cyl#7-66%
Cyl#8-38%

On all the cylinders air could be heard comming from the crankcase but on the #1 cylinder air was comming from the exhaust valve, so I dont know if the valve is bad or what, it was the last cylinder that I tested so the engine had cooled a fair bit, so I thought maybe the valve was not sealing due to that but I dont know. The heads are brand new Edelbrock 6085 assembled with only 3 years of summer use on them. So what do these numbers mean are they bad? And I also tried shifting at the higer RPM's like 6000- 6200 and the engine does not pull at all past 5500 RPM. Seems a little bit like valve float. What kind of RPM can a stock L98 bottom end put up with?

85MikeTPI

iTrader: (2)

Same thing happened to my AFR heads,
the exh valves actually bounced, not
floated at high RPMs and tore up the
valve seat..

I'm afraid it sounds like you need to
pull the heads for upgraded springs
and a valve job. It sounds like alot
of time/money, but trust me, it will
cost alot more if you don't....

mike

ski_dwn_it

That is what my leakdown test on my stock 350 looked like. I suspect that you have cracked rings as I did. Every top ring on my 350 was broken in two! I spoke with the original owner some time after finding it and he said that he knew the #7 cylinder was leaking That one was 50% plus when I tested it and it came out in about 15 pieces!

The car still ran pretty decent at 12.8 and 105MPH, but it was still way off pace from what I wanted.

Moral of the story is always use a leakdown tester for engine diagnosis, my compresssion checks all were +/- 2psi.

I would pull that engine out and take it all down and refresh the bearing and put a good set of plasma-moly rings in it if your serious about getting the most out of it. Have a good machine shop check out all the clearnaces for you, and you will be all set!

Good luck!

Clint E.

Well I had the local performance engine shop quote on a 383 and it is roughly $3000.00 Canadian which is about 2100.00 U.S. I thought that this was a bit expensive considering that they were going to reuse my rods, and use hyperutectic pistons. But looking around I found the L98 replacement from GM performance parts for about $1100.00 US which is almost half of the 383, so even if my machine just built my engine to stock specs (reused my crank) they wouuld still be more expensive. So what do you guys think will the L98 run at the 6000-6500 range?

Thanks Clint

Cruzin Kaz

Sure with the right parts the L98 can get to those RPM's Glad to hear you at least have pin pointed a problem. Sorry to hear it 's rebuild time. On a side note. The P600 Supercharger of your friends there, is he still selling it? I would be interested in the system, good or bad. Let me know please.

Thanks,
Keiran

Clint E.

Keiran,

Yes the supercharger is still for sale but the supercharger is damaged a bearing went in it, I dont know if it can be fixed. He also has the brackets and plumbing for it including the 2 core intercooler.

Clint

Cruzin Kaz

Well heck for $100 I will still buy the leftovers, and deal with the bearing thing afterwards. Let me know, and do you have any pics? how did it get damaged, or did it just go on him?

Thanks,

Clint E.

I think he blew out his oil pan gasket and ran verry low on oil starving the supercharger, He has taken back his original price of $100 after talking to a few people, I should have bought when I had the chance but I looked at it and the Impeller is damaged from hitting the housing due to the bad bearing. But the last time I talked to him he wasnt sure how much he was going to sell it for but he is still definitley selling it. I could get pictures what do you think its worth (ballpark)?

Cruzin Kaz

Well I will have to look into either repair costs, or replacement. But I would love to have some pics of what he all has. You can send them to me here. kwittmaier@cogeco.ca Please and thankyou. Once I see waht repair/replacement costs are we can go from there. Also what year is his car, as I believe the parts differ from some years to others.


Thanks,
Keiran

Clint E.

*******Ok heres some news on my low power problem*******
I decided to do a valve adjustment today on my car, so I cut holes in a old valve cover that I had so that I would not make a mess, with the engine running and warm I noticed that the both the valves for the number 1 cylinder were bairly moving compared to the others. So I took off the rocker arm and mounted a dial indacator on the pushrod, the number on cylinder lifts less than half of the amout that the other cylinders do!!!!! Does this mean I have a bad lifter??? Or a cam that has gone soft???

Please Help!!!!
Clint

mastrdrver

Do you have a roller cam? If you do I doubt it is the cam, I would think it is more the lifter.

Clint E.

Yes it is a roller cam, and at first I thought no way it could be a wiped lobe but after searching around on the board I Im beginning to think that it is. When I checked the cam with the dial indacator it was with the rocker arm off so there was no pressure on the lifter and it still was not lifting the proper amout. My thinking is that if the lifter has no pressure on it, it cannot collasspe and cause a low lift reading. Not sure if this is correct.