I know this question has been asked before and answered based on some different setups but I wanted to make sure it was applicable to my build before going ahead and sourcing one...

I have a turbocharged D16Z6 build that I am working on and is almost all complete. The car I am putting it in is a '98 DX hatch. Now BEFORE I go out and buy both an EX transmission and an MFactory LSD for it, will that EX transmission be the best bet for a setup aimed at 450-500whp or is the DX gearing "better"?

Ideally I would like to still get good fuel economy but be able to take the car to the track and not suffer too much because of using a DX transmission.

Also, I realize I can not use the same LSD between the 2 transmissions as the bearing size is 35mm in a DX and 40mm in an EX...is the DX transmission weaker because of this bearing size and therefore not something I should be using?

Semi-unrelated note...should I invest in some aftermarket axles prior to taking this to the track?

Thanks!

 

Use the EX transmisson. You can get away with stock axles if you preload them. personaly, this is just me here, but i would upgrade the axles.

You just have to pick which is more important... Loseing a few MPG's, or loseing out on the track.


EDIT- Also, in NY do you need to worry about emissons? That swap is illegal, but sometimes you can get away with it.

 

I'm with 98 on upgrading the axles. He's also correct that you have to make a choice - EX tranny for better track times, or DX tranny for better fuel economy. Unfortunately, you can't do the 5th gear swap trick like you can with a B series transmission.

If you want to get fancy, you can get a custom 5th gear for fuel economy, but honestly, the price for the part would probably take 5+ years to make up in the difference in fuel economy.

Also, as 98 said, you're putting an OBD1 motor in an OBD2 chassis, which is technically speaking federally illegal. If you have to deal with emissions and/or tight inspections, you're going to be SOL there.

 

Its simply an OBD2 ecu scan in NY. He will have to run it on an OBD2 ecu to pass. I have my car setup to swap the entire PGMFI system back to stock easily for NYSI.

 

i would just use an ex transmission. apparently it has the same 5th gear ratio as the d15 anyway so you wouldn't lose any gas mileage per se. long 5th gears are a pain in the *** to drive on the highway IMO.

 

a d-series ex/si transmission is about equivilant to a ls transmission(its actually just a smidge longer yet than a ls)

best combo i've seen is a ex/si trans with zc 3rd and 4th gears and an mfactory 4.5 f.d and lsd. that would be about as good as it gets. that should put you a bit closer to a gsr gearing which would be about perfect for 400-500whp

if i had the money i would build one without thinking twice

 

Thanks for all of the input guys, it looks like I will be going with an EX transmission and upgraded axles. Now if only someone had a used LSD...lol

 

stock axles for the win!!!

2 sets of reman axles cost me $160. they have a lifetime replacement warrentee. i break one at the track i replace with my spare and stop on the way home and swap it out for a new one under the warrentee. your stock axles will hold 500 no problem, proper launching is key. preload...preload...preload and your stockers are fine

 

Hearing that makes me very happy because thinking about finding a good used EX transmission AND shelling out another $700-$800 makes me a bit sad lol

 

or just get a b-series trans, and not worry about it. thats what i did.

 

Only difference between the two is the RPM rating for the diff bearings. For almost every setup out there this won't matter though.

Most common setup I build for customers with dual purpose cars is D16Y8 trans with helical LSD, 3.083 1st, and 4.5 FD. For higher power drag oriented setups I would go with the 4.7 FD.

 

i recommend using stock axles. they are the cheapest and easiest part of the drivetrain to fix most likely. go get the autozone lifetime axles and be done with it. ive been using autozone axles at your power goals for many years now. never actually broke one, but the outer cv joints get real loose and i say that they are clicking and replace them once or twice a year