I've got an L98 with a bumpy comps cam, ported heads, ported base/plenum/ runners, gear drive, headers, aluminum roller rockers, and accell ignition. I figured that being a tpi 5.7 my engine was factory tuned for torque. That is why all my mods have been geared toward top end and high rpms. I'm thinking about a 58mm throttle body, 32lb injectors, and an adjustable fuel press regulator. But for that money I could put the car on the bottle. How can I make more power without breaking the bank or pissing of my computer? Stop me before I go retarded and rig the thing with nos!

 

what cam specs have you got there?
from what ive read you should chase tourqe with tpi more than top end. You may be over cammed and therefore require shorter/larger runners

 

Top end, and high RPM, should not be in the same sentence as TPI with runners. I am assuming long tube runners. You must keep the cam profile to work with the RPM range your intake is tuned. This has been discussed many times. Dont expect more power beyond 4800 RPM. Yes you can rev it beyond that , but its not going to change the power cut off point. A "bumpy" cam I would guess is too much, for your combination.

Stay away from the 58mm T/B. #32 injectors are too big also.

 

the gear drive is also a no-no because it will set off the knock sensor. let me guess, with the terribly mismatched combo you have your car runs low 15?

 

scooted, what are the specs on your cam? what is your idle set at? trying to figure out what you mean by bumpy. if you've got too much duration, you're going to kill power especially on the low end. with a (ported) stock intake setup like you've got, i wouldn't opt for a cam much greater than something that looks like 211* on the intake. Depending on the cam, you might need a better intake manifold, and large tube runners. If its in the 218 -222* range, then you're going to want a full Superram intake.

What aboiut your heads - ported? what kind of work was done on them?

 

LedHeadRed...Is that you Brad?

 

why yes!

 

Cam is something like 510 duration 210 intake roller cam. If you look in the coms cam catalogue it's the biggest street/strip roller cam before race cams. It's supposed to be good from 2500-5500. The heads were pocket ported (cast flashing and rough spots grinded) then polished and port mached to the runners/plenum. Hey meanie, I ran a 14.6 at 90 mph with my old stock 305, I have the ET sheet, The gear drive is "quiet" and I don't understand why someone would log on to this site just to waste time bashing junior members. This is why I rarley ask questions on this site.

 

I'm sorry if you think people are bashing you. It sounds like you're fighting the natural characteristics of stock TPI runners. Get some aftermarket runners and forget about it. Plus if you're running MAF, how much air do you really think that stock MAF sensor will flow? 600cfm?

I'm building an engine with the opposite problem. Small comp cams XE with TPI and Vortec heads. I'm going to make my torque peak at 2000 rpm (about 430lbs). I'm wondering if that's too low even for street use.

 

scooted, the job on your heads sounds decent enough. How did you port your stock long tube runners? I don't believe there's much room to do that, if any. With that cam + re-worked heads, I would change your intake to the following:

Accel Superram manifold + AS&M large tube runners + your stock plenum + your stock 48mm TB.

Yes, an AFPR will help with some tuning at WOT.

Please do not go to such large fuel injectors. Your stock ones should be more than adequate.

I think you'll be very happy with this setup.

 

scooted45, wow so your 305 ran a 14.6, do you want me to throw a party? Thats not really an outstanding time for a 305, many 305s are there, many arent.

I'm not trying to bash you but as it was stated earlier, your combo is a little mismatched. My buddy did a similar thing to his GTA and it runs about 15.0 with an L98, ported heads, cam, runners and stock base, obviously his runners and stock base dont play well together. no one is bashing we are just offering suggestions.

 

Hey Brad....Check your PM....OK?

 

Ledhed, Iported right to the factory welds narrowly avoiding leakage issues what are your thoughts on the holley stealth ram for tpi use? It came to like 600 bones with rails, reg and Tb. That's not too bad compared to the lick'nfelter box thing. I have a harwood 6'' so clearance is no problem. Lg4, does it count as maf if you pry the screens off? Meanie I'm not butt hurt I'm just here to tap from the pool of third gen know how. Now if you will excuse me, Meanie and I have a party to attend.

 

Lg4, does it count as maf if you pry the screens off? [/QUOTE]

Yeah according to this, it looks like you're fine:

http://www.chevythunder.com/fuel%20i...ance%20pg2.htm

 

I'm sorry but I don;t know anything about the HSR. Looks like there are others on this board that do. I was going to say you'll have a hood clearance issue, but I see you'va taken care of that. I don't know how if there are alot of HSR users out there, just bringing this up in case you have problems - you may have difficuly in getting them solved....again I don;t know what I'm talking about here, so please take this with a grain of salt.

Good luck on your setup.

 

I don't recall seeing if you mentioned before or not what the car ran or how well it ran. So how well did it run before? You have any numbers for us to work with? A stock L98 should, SHOULD, run mid 14s. I agree with the fellas above, the stock injectors are said to be good for 300+ horsepower easy. If you really want injectors, 24 lb SVO injectors would be better than the stock 22 lb ones without overdoing it.

Even with a "quiet" gear drive they make harmonics in the engine that are not nice to the knock sensor. You may wanna switch to a double roller timing chain instead of the gear drive, it could be hurting your timing curve. You should do some data logging on it before doing anything. If your knock sensor is pulling timing out you will find out this way.

As for your combo, the rest of it sounds good, except for the bottle. Before you buy your blue bottle just remember the cost of refilling it every few times you mash the loud pedal with the button pressed. Besides, all motor is something more to brag about. Just my

 

In my humble opinion...

Put a jug on it and call it a day.

All the budget intake mods on Earth won't hold a canlde to spraying it. You could have the great down low of the TPI, and make up for the lack of top end power with the juice. Spray it man.

 

Well put! I bolted spray on in 1995 with no regrests.