Hey guys. Me and my dad are starting to moddify his 89 iroc with the LB9 i was wondering with hooker headers, hooker aero chamber exhaust, air foil, SLP runners, Edelbrock lower, ported plenum, and basically all the free mods what do you guys think it would run? Any recommendations as far as mods go on it? I want to get it to LS1 territory what do you guys think it would take?

 

low 14's. I highly doubt you are going to run with LS1's with a bolt on 305.

 

I forgot to mention a FPR to, and would bigger injectors help out quite a bit?how about LT1 then. Eventually it will be replaced for a 350 but right now the motor and the car only have 35,000 original miles on them so it will be a while. What about full bolt on with a bigger cam. Its a five speed to. Oh and this will all be dialed in i'm starting to do my own prom burning (wish me luck)

 

Full bolt ons along with a better cam should put you on par with a stock LT1. That would mean 13.8-14.1 territory. You will need some serious mods to hang with an LS1 though. Ive seen bone stock SS and WS6 LS1 cars run high 12's with nothing but radials.

 

well when i had my 89 t/a (mods in sig/ plus rebuilt block; bored .030 over) i raced my friends 02 z-28 with a lid and bullet muffler, suprisenly from a dead stop i held him pretty good till 65-70mph after that it was slaughter fest. You will be right there with him for maybe till mid second gear, after that the ls-1 will embarass u

 

alright just wondering what i can get out of it, cause my 305 carbed (310 really) in my 87 is running mid to high 13's so. whith everything i could possibly do to this car while still keeping it n/a what times do you guys think i could get out of it?

 

You might be able to beat a Smart with a Suzuki engine in it. Probably not though.

 

You won't run with LT1s or LS1s on the top end if you retain TPI.

You'll need a swap to carb/short tube runner FI, heads and a cam.

 

he can... I would have to figure you would need either heavily ported slp runners or a fully worked tpi with TPIS runners...

look into it.. but you would have to spend a ton on valvetrain and heads...

HOT ROD's 400hp 305

 

I think a carb setup (edelbrock performer RPM manifold, carb of choice), some ported 416's and a mild cam (218/220 range) and he'd have a mean little wee-oh-five.

 

I had ported 416's,cam,edelbrock intake and carb on my l69,5 speed,3.42's and it ran a 13.8 at reno/fernley.It would have been better at a low alt.It's wierd,some take alot of work to get into 13's but others get there fairly simple.

 

It's all a matter of a matched engine setup, good suspension and some good driving

 

well the thing is its my dad's car. i alreay have a 310 with 416 heads, cam, edel intake, carb, ect. and it is a pretty nasty 305, its alreay taken down a 94 'maro with exhaust and cai. I want to retain all of the tpi system cause i still have to pass emissions here. i just want to know how much to expect out of the tpi. And by the way is there any emission compliant fuel injection systems that could take the place of the stock tpi?

 

Super ram is the only smog legal replacement.Don't expect much above 4,500 rpm,that's pretty much it.I hate not being able to rev past 4,500.You could port the plenum and runners for a little more volume but there won't be too much of a difference.

 

There is no reasonable smog legal solution. As mentioned the super ram, a.k.a. Stupid Ram, is smog legal however it's expensive and a pain in the *** to install.

I'd just swap to a carb but retain the TPI wiring harness for an easy swap come smog time. TPI was a horrible EFI system when it was designed and it's even worse now. To quote Shifty, it was the best truck motor to never get put in a truck.

 

firstinjections.com

This looks like it would give you a lot more flow and keep the stock look (stockish).I don't know if its smog legal though.

Direct from the site:
"This FIRST® manifold can be a direct replacement utilizing factory electronics on OEM tuned port GM cars with very few modifications."

So I am assuming the smog equipment would just fit onto it.

 

why so down on the TPI? its not that bad. It was what it was, it was made in the late 80's when nothing was to fast. (im sure there will be a tone of people to disagree) Lets be honest, for a fuel injection system from the 80's, its not that bad. It makes good torque, it just falls short with the horse power in the upper rpms. Look at the good side of TPI, it replaced cross-fire injection. NOW that was a bad F.I. setup.

 

Well... My tpi setup is completely maxed out. It makes very good torque down low, but falls short in the 4700-5000 rpm range. I can hang with bone stock ls1 cars once in a while in the 1/4 but after that im done for. I wouldnt say tpi is bad for street use though. Depends on what your looking for.

 

No I think you got that wrong the TPI is great for street use just not for hwy use(where a lot of races seem to end up). Light to Light thats where a TPI shines good and short 1/8 mile races.

 

Eh well okay it wasn't bad for the 80s.. but guess what.. last time I checked it's 2006 and we no longer use 17" long runners. Most modern FI systems have approx. 6" long runners

I think even CFI has more potential than TPI, but it's more trouble than it's worth really. Just carb it imo.

Good side of TPI... it looks kinda cool That and it can be decent for a stoplight to stoplight race or a 1/8 mile run... but honestly who the hell is going to stomp on the pedal for 9 seconds at a time then let off... At some point you're going to want to rev beyond 4000 RPM and go faster than 70 mph..

 

well, my TPI car makes good burn outs so im happy for now. once i get out of college im going to swap to one of the better after market FI setups. I wish SLP made and marketed there old firehawk manifolds, Id go with that, i dont even care if there is a better manifold, it would just be cool to have one.

 

what about an lt1 intake manifold? is that possible. You guys seem really down on the tpi but i really don't want to go carb with it. What are some of the faster L98's running but still retaining a somewhat stock tpi.

 

LT1 Intake - LT1intake.com I believe is the site that sells swappable manifolds.

I don't know what the fastest bolt on L98 time is. Probably around 13.3.

 

I ran 13.4 at 100 with the mods below. I think thats about where I should be at this point. I think a FULL bolt on L98 car in perfect tune, having everything matched correctly could hit a 12.8-13.0, but everything would have to be perfect. Conditions/ good air/ traction ect.....





89 Iroc L98
FlowMaster Cat-Back, Catco cat, EdelBrock Headers, EdelBrock Intake Manifold and Runners [Both ported], Air Foil, TB Bypass, Plenum Ported, AFPR, Gutted Air Boxs, K&N Filter, HyperTech Chip , 160 Thermo, Re-mapped Injectors, MSN Ignition, Accel Rotor, Beefed Alternator, Modded MAF, 3.42 Rear End, And some new Slicks.

 

would the lt1 intake take care of everything? that looks like a really good system and might be what i'm looking for.

 

I believe an L98 could hit 12.9s but have yet to see it happen. But like you say, it must be a 100% perfect run.

phoenix - LT1 intakes are a great setup. It's so good that there are NO aftermarket intakes for LT1s. The only thing that can be done to them is a swap to a sheet metal single plane style when the car starts running mid 9s.

 

sounds like a winner then! thanks for all the help and input guys.