Ht18 Rx7 Turbo On Rb25det

[r32u]

hey got my hands on a ht18 turbo to replace my stock one. told i can get my factory exausht housing bored out to fit on so it bolts up. has anyone tried this and how has it gone? cheers

[benz_200t]

one of my friend did this conversion on a RB20det....

and he said it was slightly laggy compared to a rb25 turbo....

maybe the RX7 turbo is a good upgrade on the 25.

don't take my word for it....

for the machining part, i am not sure...

maybe you could consult a machine shop on that matter...

[bozodos]

Wouldn't an RX-7 turbo be completely unsuited to a piston motor in the first place?

[discopotato03]

I thought the Ser 4/5 RX7T's got the HT18S version .

It's been a long long time but from memory those turbo have a reasonably large turbine with a smallish compressor wheel , probably something to do with Rotors not liking turbine inlet pressure (backpressure) .

Again from memory these turbos internally were a bit like a Japanese T3 shaft wise .

As they are probably not so good on a piston motor because they have different gas flow characteristics .

Also it would be a shame to make all the changes to get it on an RB and discover it was cactus .

Your calls but I think turbos are too much stuffing about to bother fitting one that was an unknown quantity - bush bearing ones I mean . By the time you remove and reco it you've spent the price of a more modern one so why not go that way first up .

A .

[r32u]

swapped a couple of parts for it so not to bothed plus can get it bored out for round 150 so might aswell try.

once i get it going ill let ya know if its any good

cheers

[Midnight Garage]

I just bought one from a s5 rx7, that had a high flowed exhaust wheel done by Bill at ATS. It was built to suit an rb20 and made 210kw on 18psi, was apparently a little laggy but came on hard.

So who knows how you'll go with a stock exhaust side, aside from the machining. Interesting to see though!

[Fastrotor]

I did this on an rb20 nics 9 years ago , i modified the stock ecu myself to alter fuel and timing . ended up with 160rwkw on 11 psi odd. It was a fun car, i know it sounds pitifully low power these days , but it was on very low boost and just street tuned by me. We only found out the power at a dyno day after i sold it ...... to give an idea a twin turbo boosted supra made 210 rwkw on the day on that dyno.

I just had a flange plate made to suit the s4 , got it professionally welded onto the rb20 manifold, then went nuts with the die grinder smoothing it all out.

Gary

[Midnight Garage]

Yep. Cool. Well i'm still waiting to tune mine and see what its capable of, But drove it for the first time today. I'd say its boosting a touch later, but its hard to really notice. It seems a lot more willing to rev and performs much better.

No idea on current boost pressure though. Its gotta hit a dyno with some bigger injectors