First of all I am reporting my personal experiences with the ATS 4.929FD and the stock ITR 4.400FD, so this isn't going to be the "be all end all" of the 4.929FD vs. 4.400 final drive debate in terms of drag racing, but it might help some of you out with the common question of which final drive is better for drag.

First of all my set-up is a 1992 Civic Cx hatch with a full ITR swap. The motor dynoed in at 175whp with only mods being AEM CAI for 99-00 Civic Si, Tanabe Exhaust, and a kenji-spec P28 ECU.

With the car like seen above on 20x8'' M/T "baby" slicks the car turned 13.3@99mph with the ATS 4.929FD. The 60-foot time was a 1.85 and the car was running at full potential IMO because I could never break over 99mph regardless of the E.T.

Keep in mind this was shifting at 9000rpm, and when crossong the finish line I was in 4th gear at 9200rpm or so - a shift into 5th would have surely ruined the times and traps.

So in case you didn't know I broke the ATS 4.929FD shortly after my dragstrip venture - I'm sure the dragging is what lead to the ATS failure, but that's another story.

So I swapped in a 4.400 FD and I also added A DC JDM 4-1 header and 2.5'' CarSound cat. Yes this might mess with the "test" a little bit, but not much since the car was already tapped-out in terms of mph with the ATS.

With the 4.400 and on the exact same sized slicks, the car ran a best of 13.3@101mph. The thing is that this was with a sorry-*** 2.0 60-footer, while my other 13.3@99mph with the ATS had a 1.85 60-footer.

Why such shitty 60-footers? Was it the taller 4.400 FD?

No.

I could not for some reason get the baby slicks heated properly, and thus the shitty 60-footers.

I did get the slicks heated up on my last run and I busted a nice 1.8x 60-footer, but sadly enough my clutch fork broke shifting into 2nd gear so I'll never know if the car could have hit a 13.0 or dare I say a 12.99.

The car definately runs the 1/4 mile better with the 4.400FD. It took me all day of running to get the 13.3@99mph with the ATS, while the 13.3@101mph came easily on the 4.400FD and even with a horrid 60 footer on small slicks to boot.

So what does this mean for you ITR guys?

Well if you don't have a re-chipped ECU that allows you to rev the motor tp 9000rpm or so, the 4.929FD may suck pretty bad in the 1/4 mile. Had I not been able to shift at 9000rpm or go to 9200rpm in 4th my times would have been worse because I would have been into 5th gear which means an extra shift and the lost time that comes with it.

It might be different because you ITR guys have more weight to pull though - have any of you ran the 1/4 mile with the ATS 4.929FD? What rpm did you cross the finish line at and what gear were you in?

Cliff Notes:

In my opinion from my experiences the ATS 4.929FD was NOT as good for the 1/4 mile as the stock 4.400FD. This doesn't mean that the ATS 4.929FD isn't awesome on the street or auto-X, but IMO the ATS is NOT the better 1/4 mile FD if anyone's curious.

Feel free to flame away if you must - this is just my opinion based on some pretty scientific testing.

 

great info man

 

What about the differences (weather, humidity, ect.) between the two times you ran? How do you know the car wasn't putting out some more hp the second time due to better air quality?


[Modified by 6ghatch, 3:06 PM 10/7/2002]

 

nice write up.....

What works for one man, may not work for another!

 

informative stuff, however going to a 22" slick can also help compensate for going to 9K rpm ... so 20" may work best for you with 175ish HP but for guys with 200ish HP its a different story.

The ATS final also helps with burnout and launch, so that could also be a factor.

One other major factor which generally can account for 3-5/10ths of the e/t is changing from stock header to DC JDM.

Greg

 

Good info, thanks.

 

Interesting!

 

I was thinking too that slick size could help with the runs with the 4.929FD. The 20x8'' slicks are really short - TOO short - for the ATS 4.929FD.

If I ever get the ATS 4.929FD back in the car I would probably run some 24.5 slicks on 13'' wheels, but at this point I'm done spending money on this damn car.

I'm curious to see what the difference would be on 205-50-15 street tires, but I'll never know because I refuse to run street tires at the strip now after breaking an FD because of wheel hop.

The reason I used the 20x8 M/T "baby" slicks is because they are cheap, they fit under the front fenders with much ease, and for all-motor/stock motor cars like mine they work really well.

I pulled about 10 1.85 60-footers a few months back on the little slicks, so the slicks can work very well if heated properly.

 

Thats odd. I thought ats would have helped alot. Im sure the header and cat helped a bit also.

 

Thanks for the info.

 

nice review...


my feelings on it is that the change from in header performance is what made your MPH faster... the 2.5" flows alot better at your upper RPM range...

you could have also decided to shift alot faster...

shifting speed also had alot to do with MPH.. i ran a friends ITR with a higher mph over time compaired to him due to shifting...

 

What you guys are forgetting is that the ATS TOPPED OUT at 99mph - this was at my 9200rpm limiter in 4th gear. Add on the header, a turbo, whatever the mph would not change because the 99mph was gear limited.

 

Tom, good info.........but have you tried shifting at 8400 rpms, even though its an extra shift, kinda wonder if it did made any more different or not.

however, on one end. i know a few locals that have the JDM 4.7 final drive and it did make a different on the 1/4 strip. a few tenths at least. but again, this is a whole different setup (gearing).

bert

 

if i'm not mistaken, Tom already has a short-shifter, which it does help alot.

 

why shift at 9k?????
erick's racing uses 4.75 FD


[Modified by XtraFastCRX, 1:37 PM 10/7/2002]

 

Same thing happened to me when I changed to the Cusco 4.714 FD. I didn't do any 1/4 mile run with it, but my 0-60 time was slower with the 4.714FD, because I have to shift into 3rd gear to get to 60mph.

 

well guys I have got to try them all 4.4,4.785 and the ats 4.929 and I will have to say that every final drive the car got faster even in the 1/4 mile. I have I/H/E on my car and when I took it to the track with the jdm final I ran a 14.0 with a 2.0 60 and that came after about 8 trys. I took my car up to the track with the ats and only ran it three times all three times were 13.9 with 2.1 60 I fell the car actually would have went faster but I had a hard time slipping the clucth. If you were to ask my opinion I would say my car has bennefited alot from the changes. thats just my two cents

 

...Why not? Had I shifted at 8400rpm the car would have not finished in 4th gear, but in 5th.

Yes the motor drops off in power after 8100rpm, but the rpm land higher/closer to the peak power in each successive gear, so that's why I opt to shift at 9000rpm.

 

Good info Tom.

You seem to come to the same conclusion I did.


Chad who tops out @ 114 mph in 4th gear w/ATS and 205/50/15's 9200rpms

 

* wishes he could revv to 9000rpm

 

Nice review Tom That answered quite a few questions from the other thread that I previously questioned about it.


[Modified by ill phil, 7:33 PM 10/7/2002]

 

.....that, and the fact that this was on two different tracks (with ~500ft elevation difference?) and different days, temps, etc.

Nice to know, though. 101mph? Nice.

 

lemme get this straight, you have a stock R tranny, 20 inch slicks and 4.929? that works out to a 5.63 final gear!!! the gearing is way too short. with the stock 4.40 and 20 inchers, you have a 5.03 final. 20 inchers and 4.929 is too deep a gear, but that is my 2 cents...