MX-5HIT

Got a 90 with a n4a-hl, is a trans brake even possible and if so how many zero’s are in the price tag


thought it would be the cats *** to be able to just sit on the line building boost then being able to let er eat

Newaza

I've built and modded a couple of the later n4a-el which uses solenoids instead of being pure hydraulic but is mechanically the same 4n71 based tranny. I have to confirm on the clutch activation for various gears on the hl model but likely you can add a 12v solenoid valve to apply line pressure to the high/reverse (front) clutch pack while in the low 1st gear range. That should effectively lock 1st and reverse at same time. To launch you would release the front clutch. Lots of things you can do to that transmission to hold 400+hp but expect to have to go through it every couple years if you beat on it. That tranny will get you into the 6s 1/8th mile with some mods.

MX-5HIT

how easy would it be to do that? I’ve never done much transmission work so I’m a bit of a noob as far as this stuff goes

Newaza

If you've never been into an automatic transmission I would strongly encourage you to pay someone who builds transmission rather than do yourself. Its likely cheaper in the long run. Although they are really just mechanical and hydraulic devices, there are many things you have to do right and a lot that can be done wrong. I go over most of the mods I did in one of my threads.

Newaza

Also just to add.. if you were to design in a transbrake and release the brake at full boost at 400+ plus hp level and actually dead hook you would most likely break the input shaft. It is a little on the small side, so if you did a tbrake I would launch at lower boost. Although mine have held at 400hp at the track, thats without a tbrake. Plus I actually have two built identically with a 3rd for parts so if one breaks I have another to swap right in.

MX-5HIT

Mine is probably gonna be mid to high 200’s if I can get it to work right

(14psi on a 1.6 has to be around there right?)

originally had a Bee*R which I was gonna set to like 3000 and just brake boost until the ignition cut hits and spools the turbo but that’s kinda silly and I figured I should stop being a cheapskate and get a real trans brake haha