old set up

crane 2032 cam
heads freshened up
rebuild with flat top 30 over
stock intake
stock runners
stock exahust

new set up

lt4 hot cam
edelbrock base (ported)
slp runners (ported)
plenum (ported)
hooker headers
high flow cat
flowmaster cat back 3 inch
same heads

i got it to the the track for a test run and it was no faster in ET or trap speed.

best of the night was only 14.8@94 with a 2.1 60foot

now that seems way off for what this compbination should be able to run. even with bad tracktion i should have seen an improvement in trap speed

any ideas?

 

something is eeerie here. with those u should be running faster than that for sure. u didnt mention everything have u had a chip burnt for the new combination? is everything all hooked up all the vacuum lines and sensors plugged? which are u using SD or MAF? is the SES light coming on? is it spewing out black smoke? give me more info. maybe something will pop up. i m assuming u have stock heads. i would look into getting some aftermarket heads for more power. but thats not the case something is wrong here.

 

if you have stock heads that's a huge bottle neck but still, even with those mods, on stock heads you should be at the very least in 13's. what gears do u have out back? also some tuning will bring some of the power out of that combo. auto or stick? if auto, a higher stall will help get u off the line quicker.

 

the heads are still stock with a valve job, decked and just a clean up.

using a MAF

stock chip. the pocket programer is in the mail as we speak.
stock injectors


no real smoke and as far as i have seen. everything seem fine. i have reset the timing, idle, TPS, fuel PSI at 48. all the little things i can think of


i can and have been running scans. I can see that all of the sensors seem to be working.

i have an auto with a stock TC ( i know i could be faster with a higher stall. but for now i am just comparing againt what i run with the old mods to the new)

stock gearing in the back with 3.27

as it stands right now i am not looking to improve my times with more parts but to find out why i seen no improvement with my last round of mods and fix the problem



the only real thing i see is that my maf/grams per second do not seemed to have increased over last year. like the engine is not breathing any better. but i still dont know enough about how it works to say for sure

 

Well first get some decent tires, a bigger stall, different heads and replace your stock chip and that will make a world of a difference.
If that doesn't work, sell that engine

 

I think some tuning is all you need. Once you get into tuning you'll find out why you're not making more power. With the new mods you should be flowing alot more, but maybe the fuel system isn't keeping up? Fuel pressure looks like its good so you know its not a lack of fuel to the current injectors. If your injectors are running @ 100% duty cycle then maybe you need bigger injectors? Just a guess. The odd thing is you said the MAF isn't seeing more flow even with the new stuff. Makes me wonder ... The only bottleneck (or potential bottleneck) I can think of as far as the intake is the throttle body (if its still stock) but even that shouldn't be a problem. How about your air filter? Back to basics maybe? I dunno, just throwing out ideas.

 

sounds like u need fuel boy! take the screens out of ur MAF and see what happens.

 

hows that gunna give you more fuel?

if your computer isnt reading your air flow, hows it gunna know how much fuel to send eh? You could be flowing like a moflow(no pun intended) and if the MAF relay or MAF itself is crap, then you have a problem... Also, your gunna need an AFPR with all this new tunning stuff in. Im just getting into it myself, as I am presently looking for a aldl cable to at least scan and see whats going on. Your heads would be the next to be ported if anything. The hi flow runners and base are all waiting to jam more air down the cylinder, but the stock 170cc(taking a guess at numbers) runners dont do junk but slow down the incoming air. I dont know the LT4 hot cams numbers off the top of my head, but LT4's intake is different then TPI, where LT4's have a much wider power band, where TPI's is very small, even with a ported intake. TPI's like more of a higher lift then a long duration... at least thats what i see everyone getting the best results with. good luck and have that MAF checked. check if the maf is in limp home mode...

 

i ran the #s last night and i am not at even at 80%duty cycle for the injectors.

the MAF seems to be working ok. i can see in the scans that the rate of increase in flow has no odd events in it and seems to corispond with the RPM.

going to try a fuel gage on the window to see if i am getting a drop in PSI under load

 

preech all u want. the second i took the screens out of my MAF sensor the BLMS went way down and i gaine 3mph at the end of the track, seat of the pants feel is a lot better aswell. my car was running a little lean at WOT and this cured it.

 

well it realy does not mater the screen has been out for years.

i also have the air box cut and a K&N. but i still cant help thinking the engine is starved for air

 

The engine is starved for something. With a 2.0 60ft I ran 14.08 @ 97.75... I have a mild Comp Cam, and some reconditioned stock heads. AND fouled plugs!

Are you a manual or an auto? Could be the shift points in either.

2.1 isn't a horrible launch but you can still do better.

Don't listen to the guy that says the 170cc head just slows air. Technically speaking the smaller the opening, the fast the air moves. There is a point when it is too small though. With stock heads a bigger manifold and runners you should be below 14.8 that's for sure.

With my statement take example Pro Topline Pro Lightening Iron heads. The 180CC heads are always back ordered, but people opt for the bigger 200cc heads because they are redily available.

Now if you go to Procylinderheads.com, look at the flow numbers PRO Advertises on the 180 vs the 200. The 180CC heads outflow the 200s, up to a lift of about .5 which most of us don't see. And even if we see that higher lift, the better flow before that peak lift is better if you have a flat tappet camshaft.

Check your BLMS, with that much more air you're probably going to want to beef up your pump shot and acceleration enrichment.

What is your fuel pressure at? Good idea to check fuel drop off. With the extra flow you need to at very least bump your fuel PSI up 5-6lbs. Just by adding Headers to my old 305 Peanut TPI I was 2 psi below the desirable WOT A/F.

What about knocks? Are you getting alot of knock? What is the temp of your car when you race? If you are getting knocks on WOT, that means your timing can retard about 19degrees which will RAPE your performance.

I know this because when I built my 350 I put the knock sensor in too tight and it was oversensative. I backed it out a turn and noticed a HUGE improvement in response and upper RPM pull with that timing at 38 instead of 19.

You can't just bolt things on and expect to go fast.

 

Ok well you know its not the injectors then. And you checked the fuel PSI so you know its not a fuel problem. I think you are right that the motor is not flowing as much air as it should. With all the new intake mods your MAF should be registering more air. I say work from the MAF back to the air filter checking everything out. Something dosnt seem right since the flow numbers are the same before/after. The only things I can think of after seeing the list of mods (small things but maybe consider them anyway?) are the throttlebody and the plennum. The throttlebody being stock (but still shouldnt matter at this point), and the plennum maybe not being ported enough (not sure, cant say). Everything else besides that has been upgraded ...

 

hey trigger just give me your set-up and i'll see if it works good on my car

 

ok i did a few runs with the air cleaner off and no ducking to see if it was limiting my air flow.

turns out thats not it. i still need to get a fuel gauge to test if i am getting a psi drop.

on the good side i got my pocket programer today so i can start doing some tuning

 

Did you degree your cam, what head gaskets are you running, and what all was done to the heads? I think if there wasn't much port work done to the heads, there's no way your going to see a big gain in performance from your previous setup. It's more than likely that your heads aren't breathing worth a **** at high lifts where that cam peaks at. There's also the possibility of a fuel issue, because you should still be running faster than you are. I ran a similar setup on vette heads that were cleaned up, hot cam and stock intake, and I was trapping 101mph. I had several problems though and I was no where from even running decent. This was on the stock chip too. Just don't get your hopes up thinking that the programmer on its way is going to be some sort of godsend. Fiddling with chips is not what you need to be doing first when your car is this far off from where it should be. There are some cars running deep into the 12's with MAF and the stock chip.

 

the cam was not degreed
felpro head gasket (not sure why that maters?)

the heads were never ported. they were cleaned up. what i meen by that is that they were decked, new guides, seals, springs, 1.6 roller rockers and a 3 angle valve job. sorry i should have been more clear.

i dont think that a chip will help much untill i find out what the real problem is with the car. ands fix it.

 

Exactly. This is true. Little things like not degreeing the cam can add up when you're wondering why you don't have the power you should. Having the stock heads on there is killing you too. You'd easily pick up between 60-80hp by putting on some AFR's. You'd even gain around that with wome Vortec heads, but I know you don't have the matching intake components. If you can't afford the AFR's anytime soon, the Trickflow will do the job just fine as well and they are even suited better with the hotcam because of their I/E ratio.

Do the leakdown test and go from there. You may find out that you have to pull your engine after seeing the results. This is what happened to me with my 383. I'll be pulling the engine within the month. I was running 13.2's at 101 with a 383 w/AFR's, 219 cam, SR. Other guys on here are pushing 11's at around 111 w/this setup. So don't feel too awful, others are having just as crummy problems as you. But after you check all the basic stuff, start saving for some heads but most importantly do the leakdown test, first.

 

man that engine was just rebuilt last year and only has 5000miles on it. if it need a rebuild so soon

like i said before i know that my heads are hurting me. BUT i still think for some reason i should have seen some gain in power and even a slite gain in MPH on the track. and untill i find out why i will not be thoughing money and parts at it.

i also think that with my current set up (including stock heads) i should be able to run better than a 14.8@94. if i cant do any better than with i did with my last set up that would mean that my other wise stock rebuild with a cam was maxing out my heads. i just dont think thats the case . i still think that there is some kind of problem that i just have not found

 

No doubt. Stock heads are better than 14.8, seen a no problem consistant 14.5 from a friend with stock l98 heads.

Not degreeing a cam is NOT a big deal, just as long as it was installed straight up, which is what most cams are recommended for.

For instance, Comp Cams Xtreme Energy Cams are built with 4º Advance into them. There for when you install it *straight up* it's actually 4º advanced.

Install it straight up and you've got a fine street cam install. Degree the cam if you're gonna bracket race consistantly and have the time to tear the engine apart after every race!

 

Well I think you're on the right track with the maf. The motor wont make more power if its still flowing the same (or less!). If you figgure out the maf thing and see better flow, but still have less power, then I say check the engine out.

 

Maybe try to find a guy with a MAF on a car similar to yours and switch em out then test it to see if there's any difference.

 

Not true, it's this kind of attitude that separates good engines from ones that should be collecting rust at the bottom of the sea. Yeah, degreeing the cam isn't going to give you 50+hp, but its' one of the little things which is important to a good running engine, that is my point I tried to make in previous posts. Cam lobes aren't exactly always what they are advertised at, although I'm sure most companies do their best to make sure the cams are spec'd accurately.

TriggerGTA,
Just because the engine only has 5k miles on it doesn't meak jackdiddlypooh. A engine can be "bad" with only two miles it and never make the power it should. Like I said check out the condition of the bottom end after you check all the obvious stuff out first.

And also what is this MAF talk about? Your MAF is NOT a problem unless it's malfuntioning. It's not even part of your problem even if it's stock with screens, especially when it flows about 30% more air than you can use with you stock heads on your engine.

 

well i just got the fuel gage and tested the psi at WOT

with the afpr set a 50 i see a drop of 4 psi above 3000 rmp. under that its stays dead on. and as the rpms start to climbe the psi starts to drop

is that to much of a drop should you see any at all?

 

Last week my 156,000 mile 91z28 350 went 13.82 at 99mph with a 2.00 60ft. Thats a far cry from my best time of 13.11 but that was 80,000 miles ago. I have 3.42s, 160 stat, 88 gta aluminum drive shaft, air foil, ported plenum, timing at 12 degrees, 50 psi fuel pressure, put a slightly ground dime in it to get it to 50. Home made ram air behind my fog light openings. ZZ4 camshaft, stock 1.5 rockers, Stock heads,Slp 1 3/4 headers, dynomax super turbo muffler, Marsh underdrive crank pulley,Trans pac shift kit, stock chip! This motor is every tired and still runs 13s. Im building a 383 thats gonna run 11s! So something is definetley off and you dont need heads or tuning to run low 13s!!

 

You do realize that there is a max airflow rate that the MAF can register. You very well may be flowing more air through there but the MAF doesn't know about it. What are your MAF readings at when you run your scan?

 

my air flow rate are about the same from the old set up to the new one

old set up would flow about 190 grams a second
new set up will only flow about 200

the maf is not the problem. i am only using the flow # to compare from one set to the other