Hi,

Just after a little advice. I'm thinking of getting a new gt42rs and putting it on a 20b engine. Problem is, they only come in a small a/r of 1.15.

This is the new garret bb turbo, would anyone know of a larger a/r that I could fit onto the turbo to make it more suitable for a 20b.

Or would the 1.15 a/r with a small waste gate be ok?

 

That A/R should be a decent size considering how large a Gt42 is. How much Hp you looking for? Whats differant about this 42RS vs a 42R?

 

i'm wondering this as well.

 

The rs comes with a 102mm compressor wheel and the r comes with a 94mm compressor wheel.

Both have an 82mm turbine wheel.

What kind of power would I expect from this kind of setup?

The only real rear housing I could use is a gt60 which uses either a 1.25a/r or a 1.47a/r

 

what kind of porting, if any, does the motor have?
interesting about the RS. i'm doing a 20b right now as well and trying to decide on a turbo for it. i'm going to have to look into this turbo...

 

Mild port.

Wouldnt mind using a bridge, guys in australia have successfully bridge ported a 13b turbo. I don't know the exact specs of the port itself but the engine has made a little over 600hp @ the wheels.

 

I have seen over 600 rwhp on a streetport.

 

They come in a 1.01 1.15 1.32 1.47 don't remember the size. Just do some street porting and you'll be more than happy. I have three of them lying here as we speak.

 

Compressor map?

 

This isn't a flame, just a comment... Where do people come up with these names? The only thing I see in my Garrett catalog is "GT42" with the following specs:

Ball bearing option (I guess this would make it a GT42R in Garrett-lingo)
94 mm or 102 mm wheel. I guess I just don't see where the "S" is coming from

As for your question, between the two of those, I'd pick the 102 mm wheel. The 1.15 exhaust will be too small though.

Brian

 

.

 

Thanks. Read my other thread. This turbo also seems to possibly be out of the efficency rating for me? Ideas?

 

The RS comes from ATP that is what they are calling it. I just call it a upgraded wheel.

 

https://www.rx7club.com/20b-forum-95/dyno-343143/

Has a dyno of your setup there....

Makes nice power at 8 PSI. I predict (I could be wrong though!) that at higher boost levels that 1.15 might be too small though.

 

Thanks for all the replies so far.

I'm going to look at using the exhust housing from a gt60... I might even end up getting that one instead...

 

Gt60 is too big, and no need for it.

 

I ment rear housing...

 

Honestly what I would do is wait for the guy in the link I posted to dyno at around 15 PSI. This will tell you how that setup is working out...

 

Thats what im keen for. I must say, 400hp on 8lb is very impresssive. Espically on a stock standard block without porting!

 

In puerto rico there is a bridge ported 13BRE pushing over 600rwhp with a GT40 with a .94 a/r rear on C16 and around 30 psi. If they can make that much power with a GT40 on a 2 rotor and gas (no alcohol), I'm sure you can easily make much more power with a GT42RS. The GT42RS is a monster turbo, it has 102mm compressor wheel with a 56 trim this turbo will take well above 800 rwhp on a 20B if you boost enough. If your goal is only 600rwhp you could do that with a GT40R with an 88mm compressor wheel. I recommend that you look into Innovative turbo they have some very very nice stuff, like the T80's. BTW I have a 13BRE with a GT4088, I'm expecting well over 500 rwhp on C16... What I'm getting is that don't stress your turbo too much man, it'll take well over your goal.

Good luck with everything,
Alex

 

They are all very nice figures but the car will be driven on the street and the drag strip every now and then, its not like i can get c16 from the pump at my local shell.

I'm just worried that the small exhuast housing will not be able to keep up with right boost/rpm levels...Thats why im waiting for a 15lb run for the other users 20b.

 

I've seen 830rwhp on a streetport.......

 

I'm only interested in specs with this turbo and a 20B.

Nothing else...

Damn good number though!

 

If you want a good turbo and you have the bucks I recommend you get an innovative turbo. 20B, with a T78 q-trim standard bearing, pump gas, 14 psi put down little over 600 rwhp, Also I said I will easily see over 500rwhp but I'm looking for 600rwhp plus... and the 20B is driven on the weekends, and my car is daily driver. You can do whatever you want man but trust those of us who have personal experiences with these motors and set ups. That rear housing is even small man, that turbo will super efficient up to 32 psi.

Alex

 

BTW why do you need 600rwhp every day driving on the street? C16 is pricey, but it's reliable and healthier for your motor. Best of luck man, hope everything works out great for your.

Alex