I see a lot of people wondering about the gains you can expect, and I just thought I would help out. I've owned my 88 Formula 350 for two months and have done these mods in the last 5 weeks. I've kept track of my gains with my g-tech. As we know, the g-tech isn't perfect, but our track (thunder valley) wasn't open at the time.

So, here we go:

Stock my 0-60 was 5.95 and the 1/4 was 14.6.

We descreened the MAF, removed AIR & the smog pump, added hooker headers, 8mm Taylor wires, Bosch +2 plugs, and SLP airfoil. This (with open headers still) gave me some huge gains. My 0-60 was 5.42 and the 1/4 was 14.00

Then, i went to my local exhaust shop. They added 3" single exhaust all the way back and a magnaflow muffler. My 0-60 was then 5.62 and the 1/4 was 14.15. Yes, it slowed me down.

Just two nights ago, I put on the UDP's and made a new personal record. 0-60 at 5.39 and the 1/4 at 13.86

So, that's where it stands right now. Not bad for under a grand. Soon, i will add my homemade K&N intake, AFPR, 3.73 rear end, and 160 thermostat. We'll see how that works. By the way, all these results were taken on the same road to ensure accurate comparison.

 

What about weather, wheelspin, and most importantly, MPH?

 

Oh...those details. Ok, I can't remember all the mph numbers. I was more fascinated with the times I was clicking off. If I run it tonight, I'll check it out.
Weather and wheelspin I can definitely answer. All of the runs were done at about 60 degrees, because generally I only drive the Formula in nice weather. However, the morning when I ran the 14.00 with open exhaust, it was 15 outside. We had a huge cold-front come in.
As for wheelspin. The first two runs I mentioned were with no wheelspin. My Sumitomo's are very sticky. I run 255/50's at the back. Anyway, I decided that when I heat them up and allow no wheelspin, it's actually slower b/c it boggs. So, now I just punch it pretty hard, and it spins moderately til about 4000rpm(1st gear). That is the way I ran the 14.15 and the 13.86.

 

What are UDP's?

Are you using the first G-Tech or the new Pro-Comp?

 

Sorry, that was my abbreviation for UnderDrive Pulleys. And, my gtech is the earlier model.

 

See, thats what i was afraid of. If you did the 14.00 @ 15', and the 14.15 @ 60', then you didn't really slow down, the weather could have easily made all that difference.

As for the wheelspin, unless you're running way too much cam for your converter/gears, wheelspin will always slow down your ET. Thats one of the more common novice mistakes at the track is to go for the gusto and end up spinning off the line instead of nursing it and letting it hook-up. And for comparison purposes, numbers with wheelspin get really fuzzy. Even similar feeling amounts of wheelspin can actually be pretty different in terms of how it is hooking up. Unless you're at a track and can compare 60's, i wouldn't try to draw comparisons between numbers that involved spin either.

But other than that, your numbers do basically make sense given the built in variation. 1/2 second between headers, tune-up and a de-screened MAF is reasonable. Basically nothing out of a cat-back is also pretty much normal. You're claiming 3 tenths from the pulleys, which is on the high side, but given wheelspin that could easily be varying a tenth on either number making it completely normal.

I'd recomend skipping the 3.73s, TPI cars really don't need gears. Besides, your 88 probably has a 9-bolt anyway, making a gear swap cost prohibitive. For the same $$$ you could get a converter instead and be way ahead of where gears would put you. And with a converter your cruise gas mileage stays exactly the same because you still have lock-up.

 

Well, that kinda changes my thought a bit. I was supposing I would lose 2 tenths by changing to 3.73's. Do you think that upgrading my TC would help me out that much. By the way, my Formula isn't my cruising car, so if gears reduce my mileage, i'm still fine with it.

 

Thanks 88Formula - I just hadn't heard that abbreviation before.

 

Here's a thread from when i first swapped converters doing a comparison: https://www.thirdgen.org/techbb2/sho...r+undiscovered

And thats with a 3k stall thats really overkill for a completely stock engine, and in a heavy 3.23 geared convertible. Another great example of running fast with a converter and little else would be a member called Thirdgen92Z28 (or something similar). He's running mid 13s with 1.7 60's with a basically stock engine and a 2400 stall converter (and 3.23s).

Beyond that, EVERY person i know running a good converter will tell you it was the best single mod they ever did. You won't often see stock converter cars running good good 60's (sub 1.9), even with gears.

I don't know what else to tell you to convince you though. I'd guess if you tryed a search on 3.73s you'll find plenty of posts with people regretting the move. Or at least a lot of 14 second cars with 'em. As for converters, take a look at what all the faster guys are doing. You'll find that everybody is running a converter.

 

The problem with big gears and TPI, is that TPI, by its design, disables the engine's ability to continue to produce power past 4500 RPM. So if you put in too much gear, you end up with a motor that just jumps up to 4500 and hangs there as it goes down the track, and doesn't accelerate at all the last 200' or more.

Ed's right, TPI more than any other induction system will benefit from a higher stall converter used with a moderate gear such as 3.23 or at most 3.42. 2400-2800 RPM stall is where it needs to be. Any more gear than that, and you end up with a car that doesn't kep accelerating all the way through each gear. TPI just doesn't work like a carb motor with a big single plane intake where it has no bottom end and a big top end, and you can't build a car around it as if it was that way and expect to go fast. Numerous people have reported that they actually slowed down with 3.73 gears.

 

Awesome, I appreciate all that. I'm reading that other post right now, learning some stuff about Torque Converters.
So, perhaps, I will save the 3.73's for when i port my manifold, runners and plenum. It would be beneficial then, with some more power up top.