I'v searched and have only found one person with this large of a hot-side.

Anyone running a 1.32?

I currently have a 1.0 going on a T04Z rebuild and would like consider moving up to minimize back pressure as much as possible to gain the highest top end and lowest EGT. Is 1.32 just too excessive?

My old 440rwhp dyno run showed power trailing off around 6.75k rpms and I'd like to make power all the way to 8k on my large port.

 

i have a customer running a 1.32 in a borgwarner s400

 

I'm running the 1.32 t6 s475, love it, but all I do is drag race, laggy when we go for a blast arround the shop..
Most of the time when your looking at that big of a hot side it's a drag car and making 6-700 ish, we made 733 @30 psi

 

Assuming its too big for a T4, divided, 67mm with goals of 550rwhp?

 

1.0 is enough to make peak power in the 7500 RPM range. Look elsewhere to get more top-end. Start with your tune. What manifold are you running? Going bigger then 1.15 on a streetport is silly unless your gonna run drag boost. And even 1.15 is starting to get laggy.

What dyno did you use? Its possible its just inaccurate RPM recording on the sheet as well. That is why I only use Dynapac's now cause the question of RPM accuracy is always a problem since rotaries very rarely give a stable pickup reading.

thewird

 

My previous turbo was a GT4088 with a 1.06 AR turbine housing and was running on a large street port. Power started to fall off at 7500rpm but made over 550WHP. You could probably search my user name to find the dyno sheets. I think the 1.32 may be over kill but you may need something in-between 1.0 and 1.32 to get close to 8K.

 

1.0 should be enough for your goals. Best size for a street car with occasional track use.

 

TheWird, I'm running the HKS Divided Cast Manifold, w a hybrid T04S DBB, (turned into a T04Z). Dynojet, and that's interesting about the rpm being off, maybe its truly the cause.


On my previous setup, with 60mm compressor and 1.0 AR, I made 440RWHP at 6.5K RPMS, power begins to trail off until 8k. Its noticeable when driving the car that it doesn't continue pulling you to redline as hard.

How much spool am I looking at sacrificing going to the 1.32? I'm perfectly fine moving up from 3500 to 4000rpm or even 4250rpm. If I can spool ~4,000RPM but make power all the way to redline that would be great.

Having a large street port, the most power should be made between 6.5k and 8k. If opening up the hot-side is the key, then perhaps I won't need as much boost, and egt will drop making it less stressful on the block?

 

The 1.0 isn't the problem. Probably needs more timing up top. Do you have any logs? The HKS manifold is probably part of the problem but it can be worked around.

thewird

 

Well, decided to go with the 1.0 AR and P-trim clipped turbine.

Have to wait and see how it does on the dyno once its back together

 

I like the 1.32 divided housing on my T04R, I went from a .94 undivided housing to this and a 4" exhaust and while it's not a perfect comparison, I got quicker spool up and the power stays up in the higher rpms unlike before, check out this post here and a dyno sheet comparing the two setups https://www.rx7club.com/time-slips-d.../#post10990818 . Power for both setups was the same at 7k but about 60hp more at 7800 rpms with the 1.32

I don't get 22 psi boost until 4500-4700 rpms.

 

Thats exactly what I was thinking! Awesome!

Maybe I should have gone with a 1.32, I may just do that. I have no problem with waiting until 4500k to start spooling if you can pull harder and harder all the way to the end of the gear.

 

Years ago used 1.75 also ended up using 1.32 divided on TO4E. 13B on alky, went like stink dirt track speedway.

 

Well, I kept 1.0 AR and just moved up to the 67MM. I'm going to try pulling the catback, touching up the tune, and seeing how it pulls. If power still falls off at 6.75k then I'll go up to a 1.32

 

It's not the 1.0 for ***** sake, its something else.

thewird

 

Which is exactly why my last post said I'm going with the 1.0...

 

I use a 1.15 a/r