NVRENUF

Hi,just looking for some advice/help/possible solutions. I recently installed a complete SuperRam set up...base manifold,plenum,52mm throttle body & was expecting a significant performance increase but instead saw absolutely no e.t. or m.p.h. change at all over the stock T.P.I.

Here are the specs.....'89 IROC,5.7,64,000km (approx 40,000 miles) Crane Compucam .452/.465 lift,214/220 dur.,stock heads are ported/polished,3 angle,back cut valves,screw in studs etc. Hooker Comp. headers,MSD 6A,stock bottom end(engine has never been out),TCS 9" 2800 stall Prolocker converter,trans other wise stock & original. Dana 44 rear end,3.54 ratio.Walbro 255 l/hr fuel pump. Hyper tech chip,pullies,AFPR.Stock injectors.Modified MAF.Flowmaster.Custom ram air set up. I've owned it since new,immaculate like new condition.

Here are the problems....like I said,no e.t. or m.p.h. change at all over stock T.P.I. Took the scanner from work & took snap shots during a run,most times getting from 12 to 17 degrees of knock retard,O2 readings seem to hover around the 500-700mv range,have at times dipped into the 300-400 as well as the 800's...so ??.Always run 92 oct. fuel,car is fanatically maintained by me. I have tried almost everything & no change. Ran C-16,no help,changed O2 sensor after to be sure not contaminated.Fuel pressure has been from 45-55 psi with no change.Thought Walbro fuel pump would help,nope (needed it anyway) Ran with open MAF(no snorkel for possible restriction) nope. Ran it with the stock chip,no change.Timing is set at 8 deg.

Car has run a best of 13.2 @ 102 m.p.h. with 1.78 60' at 2400' alt.
With the SR,I was expecting mid 12's. I have been a technician at a GM dealer for over 12 years,so I have access to any & all GM specific info/data/diagnostic aids etc. As well as alot of other experienced brains to pick at,but we are still not sure what exactly is going on. A friend of mine (who is currently making his 11 sec Syclone into a 10 sec Syclone...the bastard!) is the tune up guy at work feels that the car should be changed to speed density & custom burn chips for it...which is what we plan on doing now. He has a friend of his (also has a 11 sec & possibly 10 sec Typhoon) do the chips for his truck & they have worked out really good,he has a real knack for the whole chip burning thing. We plan on using a Syclone ECM to do the change over as I plan on building a ProCharged 406 at somepoint in time (as in $$$!) so it already has provisions for boost. Any advice or problems to watch out for when doing the change from MAF to SD are greatly appreciated.

Could the stock injectors also be holding it back? How far has anyone gone with the stock injectors? We also think that I could be starting to push the limits of the MAF. The car also surges at idle once warmed up,no vacuum leaks found either,otherwise runs fine. Could it possibly need another cam change? I see the one Lingenfelter recommends for the SR has considerably more lift than mine (dur. is similar). I was planning on installing Crane's 1.6 roller rockers as this will somewhat mimic his recommended profile,still have less lift but closer.

Sorry for the length of this,but I wanted to give as much information as possible to try & help anyone who reads this get the full story. I greatly appreciate any & all help/advice you may have. Thanks again.

Steve

egmonster

I'd say it's the stock heads since you are probably not leaning out as I'm sure you know what's going on with your car. This is a sign that no additional air is going to your cylinder heads of course . That is a nice time for stock L98's so I would be pretty happy if you got the same #'s with (I assume) a nicely ported stock TPI setup. I was planning on doing some home porting next weekend on my heads so I'm glad to see the kinds of times that can be had with all stock equipment . What kind of suspension mods do you have? You must make some pretty crazy torque to get down the track that fast at that altitude with that ET and Trap .

egmonster

Actually it could be the injectors too I just reread your post and I am stupid so what can I say . I'd say it's probably a combination though. Definately upgrade to some 24 or 26lbers though.

86ZZ4

It appears to be running lean, I know 02 reading @WOT are not a very good indicator , but 500-700mv is way low.Been a tech @ GM dealer for quite a few years also ,and we are fighting one with simalar problems.....Blazer with ZZ4 and super ram, its a PIG...... it also has very low o2 readings.Stock prom with 24lb SVO injectors.Even with stock PROM it should run decent being MAF , and ZZ4 's are not that wild a motor.

NVRENUF

egmonster...not sure about the heads as they have been done but I definitely want to get some AFR's someday...$$$! I had been running 13.7-13.8's before I put the SR on,but,like I said,absolutely no change after it was installed. Then I put the TCS converter in & that was worth .5 sec alone. 60' went from 1.98 to 1.78 Highly recommend a converter to anyone! As far as suspension goes it's all bone stock original (for now anyway's) & I run ET Street's 10.5x16..highly recommended,very sticky That's what I like about my car,looks stock (with the hood closed ) but goes like hell.. and NO NOS!!!ould be doin' but now I want 11's Once we change to Speed Density then we can get some better,more comprehensive data to see what's going on.

86zz4...I can't remember the exact O2 readings as they were done last fall (last few races of the year) but I think that's about what they were. I know they varied,sometimes relatively ok..in the 800's but sometimes not. The engine run's great (except for the idle surge) other than that,it runs almost perfect. Friend of mine is about done his Syclone so hopefully we can all get together now & try & figure mine out. Also checked fuel pressure at WOT & stay's steady. Once we get some data hopefully that will tell us what's going on with the injectors,as far as pulse width goes.

egmonster

Ahh yes, I have a new torque converter and tranny that should be arriving any day now . I also have new shocks springs, LCA relocation brackets, adjustable LCA and panhard bars coming . As well as a new torque arm. Woot.

NVRENUF

Thank's for the input

Anybody have any other thoughts/possible solutions etc.? Still wondering about the stock injectors at this point. Also,any problems or concerns to watch out for when doing the MAF to SD conversion? Just trying to get as much info as I can before we start the conversion.........Any & all opinions welcome!

...new best 60' today...1.76 on all stock suspension..ET Streets kick ***!

Thanks again

89gta383

iTrader: (5)

I don't think the 165 ecm is your problem. I ran 13.02 @ 106 with no tuning with that same cam and superram on a 383 with like 9:1 compression. With a convertor and a gear it would have gone 12.50's @ 107-108 easy.

I used to get high knock counts like yours also. You have to watch those small cams, they build cylinder pressure very early, so you have to tailor the advance curve accordingly. Also, I always got a crapload of retard right after the 1-2 shift and 2-3 shift where the load on the motor was the highest after being pulled down with the 3.27 gears.

Turn your initial timing back 2 degrees until the knock retard stops, then you will know how much timing you need to pull out. I picked up from 80-83 mph in the 1/8 mile just by retarding my inital timing from 8* back to 0*. I was getting like 15 degrees retard.

You need to scan the whole pass down the track to know whats going on. I used my autoxray, and after the run, plotted each data point on a sheet of paper. Maybe a little behind the times, but it works better than nothing. Then you can see where you need to add fuel and timing. You are running lean and have too much timing at the exact same places that I had.

There is nothing wrong with your heads, the injectors maybe a little small, but they will work. You need some fuel added in the chip and a timing adjustment.

Let me know if you need help with your bin.

JohnnyIroc

iTrader: (3)

i dont know man, look at my sig......i ran very close to what you ran and i still have stock heads and intake. You should be in the 12's with a decent head swap thou. later

NVRENUF

89gta383...not sure about the timing thing though. I will set it back for this friday night's drags & see what happens. Hell,tried everything else already so it can't hurt!! The plan is to use a Syclone,Typhoon ecm so when I do build the Procharged 406,it will already have provisions for boost control. Plus once we get it done then we can use Datamaster to moniter everything to see exactly what's going on. In particular,the knock retard,O2 readings & pulse width to answer the injector question. Is your's still a MAF car? I assume so. As far as the bin goes,possibly might need some help,depends on how much info etc we come up with. If anyones interested they can go to www.syty.net/ & check out or follow along on the building/tuning of my friends Syclone,it's running now & they are using DIY wideband tuning set up to dial it in even better. We plan on using that wide ban on mine as well. Just do a search for the name turbotony and right now it's under the thread titled "stretching the stock ecm" The chip burning/tuning "guru" is canadian sy/ty. Just puttin' that in here in case anybody may be interested in the tuning aspect......not an F-body I know,but kinda interesting.

TheRoc88

Set your initial timing to 0, the ECM does the rest. Your losing tons of power by changing the dist. all around. Leave it at 0 like GM told you too and you should immidiatly see an improvement :lala:

Mkos1980

iTrader: (8)

Base timing for a TPI was 6* from the factory.