unknown_host

iTrader: (1)

Hey guys,

I was told by someone in the Organized Drag Racing forum that this is the place to learn about making my TPI car faster.

It ran a best ET last year of 14.6 @ 94.5 on a 2.25 60', it's a mostly stock L98 with a 3" Magnaflow muffler, 2.77's and a 2800 converter.

I bought a set of drag radials for it and put a set of 1 5/8" shorty headers on it this winter, I will be racing it again in 2 weeks.

Any suggestions on bang for the buck to break into the 13's?

DiabloWS6

iTrader: (8)

I would suggest 113 Corvette heads as bang for the buck plus they will make your car a bit lighter

godreject

iTrader: (1)

taller gears, have you done the freebie mods, gutted the air box. also what brand headers.

Orr89RocZ

iTrader: (20)

Headers will help. Advance base timing to 8 deg or chip tune it. Sticky tires and 2600-2800 stall is all you need. I went 13.89 on stock type 245/50/16 street tires with those gears and 2800 stall and full exhaust

Kevin91Z

iTrader: (1)

I wouldnt. The corvette heads have three major problems that make them less than desirable for our f-bodies.

1. They have the old style intake bolt pattern, with all 6 intake bolts at the same angle. 87+ f-body intakes have the center four bolts at a different angle. Your stock f-body TPI intake wont bolt up.

2. They dont have EGR passages, so you'll need to run the corvette style EGR passage from the header to the EGR port on the back passenger side of the intake manifold. Getting either a corvette TPI intake or an aftermarket TPI intake will help with this problem, and the above #1 problem.

3. The corvettes have different front accessory brackets, so their heads are missing a bolt hole that f-body accessories need to bolt up. You can drill and tap this hole if you know how.

My opinion is the biggest thing holding you back right now is your gears. I'm guessing since you said 2.77 you have a 9-bolt, and its near impossible to find a 3-series carrier and 3.27 or 3.45 gears to change it out. You probably will have to change out the whole rear end to another 9-bolt, or a 10-bolt.
With the headers and stall converter you have now, you're almost there. A set of drag radials will help a ton for now. Advancing the base timing to 8-10* at the track, along with the other free mods, will help as well. Dont forget you'll need a helmet for 13.99 or faster. Good luck!

NufNuffZ28

iTrader: (10)

3.42 gears
more stall
10* initial timing(listen for detonation)
gut your airbox
high flow cat



Friend did it with stealth ram, DRs, stall and gutted airbox(I know you want to keep TPI, just throwing that out there)

Orr89RocZ

iTrader: (20)

Heck stealth ram, full suspension, full exhaust, ram air box mod, 1.6 rockers, lean tune, drag wheels, slicks and 3.42's on a cooold air day my L98 went 12.9's. doesnt take much to make these motors work, if in good running condition.

unknown_host

iTrader: (1)

I am running Hedman shorty headers and y pipe. To clarify, I added the drag radials and headers this winter so I have not run the car yet with those installed.

I actually do have a set of 3.23 gears and a 3 series posi for my 9 bolt, I was debating whether it would be worth the money to have them installed or not as it isn't a big jump in gearing.

Is an AFPR worthwhile? Thanks for all the advice!

NufNuffZ28

iTrader: (10)

gears are worth it...the afpr is Only worth it if you're going to dyno it and get the AFR dialed in...

Yeah Orr, beside what I put the 91Z was stock. Impressive for the mods....

Think it was a 13.7 and 12.20 on 150 shot

Orr89RocZ

iTrader: (20)

You dont need gears to get 13's but gear does help on these cars. You NEED a good torque converter. 2600-2800 will get that car into the 1.7's 60'

Kevin91Z

iTrader: (1)

Read it again, he already mentioned a 2800 stall converter.

Do you have 3.23 10 bolt gears, or 3.27 9-bolt gears? 10 bolt gears and 9 bolt gears and posi units are not interchangeable.

Orr89RocZ

iTrader: (20)

Oops. Yes he does. Then you should be set once you get tires. Id run as is after headers and drag radials to see how you like it before changing gears

DiabloWS6

iTrader: (8)

Yes there is more issues running 113 heads to convert over to an f body engine but isn't being lighter the name of the game especially 1/4 mile yes there are better heads out there than 113 bang for your buck i got mine cheap, less weight out front better balance not a whole lot but every bit off weight counts

IrocZ442

A 2800 is a standard upgrade stall for a replacement. So I wouldnt count on anything with that esp with out a Shift Kit By Trans Go.

Orr89RocZ

iTrader: (20)

Are you saying 2800 wont work for a car that needs to shift by 4500-4800?

unknown_host

iTrader: (1)

No kidding either that or he is saying that 2800 is "standard" like stock? Much looser than stock .

IrocZ442

Dont get me wrong a 2800 is what I have an I have a full out built, all hard parts upgrades, pumps vanes. 700hp.. And Trans performs Tops. 3rd gear bark.

DiabloWS6

iTrader: (8)

Nice

Orr89RocZ

iTrader: (20)

Just based on the converters i used, 2800 is a substantial difference maker over stock. I wouldnt go higher as torque peaks lie in the 3000-3200 range and after that it falls off to rapidly. Peak hp at 4400-4500 so rpm band is short. 2800 is about perfect for a tpi car. Hsr can go 3000-3200 on stock cam but 2800 still works great

IrocZ442

So what were saying it's not your stall.. Thats fine.. Rear end Id change later because your starting with 2:77's..Light mod L98 with 2:77's can get in 13's range. A Head cam combo be what your looking at to make power. That's the first thing I collected.

Mikos_89

Well...if he's looking for a cheap and "easy" way, wouldn't a small shot of nitrous do the trick??

ringo234

When I changed from a 2.77 open differential to a 3.42 posi it made a huge diffence in getting off the line. The top end suffered because with 2.77 it could keeping gaining speed for what seemed like forever, but I was well passed a 1/4 mile by then.
But the real difference came with my 355 upgrade from mt stock 305.

TA

iTrader: (1)

You already have the 3.2? gears and the correct posi unit for the 9 bolt? That is sure where I would start, especially since you have some sticky tires. Your launch will see a big improvement over the 2.77s.

But Kevin is right, though, make sure they are for the 9 bolt and not the 10 bolt, or they will not work.

TA

chazman

iTrader: (4)

With the DR and headers, you may already be pretty close. Do the free/cheap TPI mods, and I'd bet you'd be there.

unknown_host

iTrader: (1)

So just an update to this thread, the car went 14.19 @ 96.5 (I think) on a 2.0 60'.

I have another thread where I posted the timeslip, but since this came back from the dead .

I am certain I am undergeared for my converter and just not 60'ing great, my converter flashes up high and the car reacts hard, but the car just doesn't take advantage of it.

Thinking of doing something a bit more drastic to get this thing making more power.

unknown_host

iTrader: (1)

To expand, I think I can put the 3.23 gears in and pick up 2-3 tenths and maybe 1.5-2 mph which would most likely put me into the 13's, or I can invest some money in the top end of the motor. One thing about bracket racing a TPI car, they really fall on their face up top. I hate getting mph'd on the big end, and even racing a brand new V6 Mustang I was at about a 5 mph disadvantage on the big end.

IrocZ442

Heads an cam 24lb injectors an tune fpr.

ninetyone

iTrader: (2)

Custom chip will help a lot.

Orr89RocZ

iTrader: (20)

L98's do respond well to intake mods. Shorter runner intakes or heavily opened up bases and large tube runners or better yet large tube siamesed runners. They shave off a good bit of time and well worth it on the top end

IrocZ442

No other way.. Id say Super Ram if you want to stay above the motor. You will gain power trust me I did it.