Hey guys, I got my car dynoed this weekend for 312whp and 284tq. Of course it's quick, but we all know it's an addition and I want more!

Wondering who here has around 400whp and what it took driveline-wise to get there. I have all the supporting mods under the hood, but from what I have read I am concerned my stock 6 speed, and stock diff/axles won't reliably put up with much more.

 

I don't know, but I like your NACA ducts leading to what I think is brake ducting. Great idea.

wait...axles should be good, unless launching at 4k with slicks. Trans- the new K miata e series trans looks like the easy button.

 

intended use dictates supporting mods
Plenty people street drive 400whp Miata's on the stock 6sp, diff, and axles.

Racing, not so much.

 

thanks!
and I saw that! now if only i could find a spare 2,800 laying around lol! I will probably end up going that route in the future, seems like the best swap-in solution.

does anyone have experience on limits with stock diffs? I have a 4.1 torsen and was going to get the 3.63 r&p but I dont want to spend the money converting it if its going to pop, but then again im not quite in the market for a getrag yet.

 

I do OTDs, auto x, and drifting with it - until i get a dedicated drift car at least. I'm definitely not easy on the car but I also dont launch it really ever. just clutch kicks

 

don't worry, you'll probably stuff it into a wall before you break the transmission.

 

Anything north of 350whp is borrowed time for the 6 speed. People don't break 1.8 diffs a whole lot, unless there is a large amount of hoonery involved. My solution for now, is to keep a back up 6 speed. I can toss a new one in within 2-3 hours. I can't really say anything, the car hasn't been to a dyno since 'nam.

What kind of turbo do you have in there? I may be speculating, but maybe a larger one is in order?

The BMW trans is tempting, but if I'm going through the effort and money, why not k swap while im at it?

 

thats true! I have a borg EFR 6758 which says its good for up to 500hp range

 

I see, I was just confused why you were so soft up high. It looked like you were running out of turbo. You can get 400whp by revving more, building more boost in higher RPMS. It is torque that kills the transmission. If you were to keep your torque past 6k flatter, and up your rev limit a little, you would be at 350 easy.

 

I am doubtful the 6758 will hit 500whp on a miata motor. Soviet his around 450whp with E85, all the boost, and I believe he saw signs of det on his pistons when he last looked.

 

he said hp

 

thats true, huh.. now im wondering why it got soft up top too.. :(

 

I'm pushing around 400WHP for about 5 years now with six race events per year. I'm using a 6 speed and miata rear end. So far, no issues. I have a spare transmission and I rarely do drag race style launches.

 

On a stock VVT head. With a worked over head he could do 500. Det was from the pre-e85 days. You won't detonate on e85.

To OP. You need e85 or race gas if you want to make that much power on a 6758. I just did 380whp at ~27psi, and would never continue to run that much on pump gas.

 

*****

 

My wallet is a giant *****. Write me a check for a new motor and I'll go do 35psi pulls

 

Once I get my turbo to stop puking oil I'll put my ID1000's in an do them for you.

 

I did 27psi with my turbo puking oil

 

Challenge accepted

 

You're going to give poor six shooter a heart attack...