hey guys i just bought a 20b , im making my car a monster and will not except anything under 500 whp!

 

well 500rwhp is not very hard to obtain.. i would not consider that to be a monster with a 20b.. if you really want to make a monster, prepair to spend some money. but a gt55 is a nice match in case that is what you want.

 

There is an abundance of threads in this section to help your research want you want to do and make your car a monster. Do a simple search and see the results that people have made over the years.

Plus you wouldnt want us to tell you what to buy, its your car

Good Luck with the build, hope you have some deep pockets.

 

+1.

gt55? that's huuuuge! i run a bw s480 on my 20b.. love it.

 

how much power have you made with that?

 

Gt55, why?

Gt42R is a very good turbo size for the 20B..

15psi is over 500rwhp without breaking a sweat...

 

I'll be running NA with high comp rotors and a race port, hoping to make a high 300whp number.

 

because its a 20b. if you want a gt42, you should put it on a 13b in my opinion.

 

GT55 is overkill for a street driven 20b.....a 42R will give fast spool and plenty of power.

 

what is the difference between a 42r and a 4202r ?

 

It has a 102mm compressor wheel:

(scroll down to large frame)

http://www.turbobygarrett.com/turbob...ochargers.html

 

lol goodfella you beat me to it. I was acually going to buy one in about 2 to 3 weeks from now. my best bet is a gt45r its inbetween a gt42r and a gt55. im going to give you an idea of what im going with. GT55, full bridge port, whole motor balanced ( shaft,rotors,), low compresson rotors,6 additional injectors, 4" accufab mustang TB, 3mm apex seals dunno yet have to decide what kind, hardend oversized engine bolts, race bearings. best thing is look for real good apex seals, IM prob going with eather ALS RACING SEALS, PTS APEX SEALS or RA SUPER APEX SEALS the black ones. Thats what i have in my FD right now the 2mm ones and iv had never had a problem with them and i was boosting at 23LBS. If you are wondering who i am im the guy that bought Brians Black FD from Georgia i remember you guys were having some discussion on his forsale thread about you wanting something back lol.

 

O i forgot to mention pineapple racing sells reusable water seals and iv heard they are very good. Im deff going to go with that.

 

For your hp goals, a GT-40r is a better choice. It will spool faster than the 42r for better bottom end and there is still enough compressor left for 600rwhp if you should decide to raise the boost.

 

i have GT35R, should i even consider putting it on 20B?

not looking for high hp, but for lot of torque and very fast spool....

no more boost than 15psi

 

No, way too small of a turbine wheel/ and available housings for the 20b. Personally I would only use a T6 flange'd turbo..

 

A medium frame turbo isn't going to work. For a stock ported engine, you would want something that can flow into the 60-70 lbs/min range, such as a T-64, T-66 or GT40R.

This sounds pretty close to what you are considering:
http://www.7parts.com/forums/viewtopic.php?t=12

 

Link you posted is 20B with 9.7 compression ratio na GT40R

Well, what exactly will happen with GT35R on 20B with stock 9.0 comp?

With properly sized exhaust manifold and large enough wastegate (i run HKS GT 60mm right now), i am guessing it should do no big harm to exhaust flow and as well should be no worse in power compared to current setup (15psi on ported S5 block)

Or am i completely wrong?

 

35R is a 61mm compressor wheel, I'm not sure that the analogy can be made to running a 40mm comp wheel on a two rotor but I'm pretty sure the 35R is all around too small.

Keep in mind the 35R is considered too small by 13B guys looking to make serious power

 

Gt35R uses a BIG t3 turbine wheel, and generally a T3 turbine housing( ATP sells a T4, but its just a T4 flange on a T3 housing). Most of your flow goes through the turbine, and a big wast-gate can't makeup for too small of a housing. If that was the case we would all run t2 housings with 4x 60mm gates...

If you want to run it like a truck built v8 engine go for it, don't expect any power over 5k rpms...

 

The gt35 has been proven to make 500whp on a 2 rotor and will do the same on a 3 rotor. Only difference is the larger displacement and exhaust energy will spool the turbo much faster for a **** load of bottom end. It will easily feel like a v8 but run out of breath in the upper rpms.

 

... which is perfect for making a lot of torque and fast spool.

The smaller turbo will choke and/or blow hot air at the higher engine rpms, and the stock compression rotors will have a bit less low end torque and slightly slower spool but will handle the boost a little better.

Based on the compressor maps and some quick ghetto calculations, it looks like the GT35R will run out of steam around 6500 rpm. As you can see, the GT40R looks much better.



I think the GT35R will have some flow problems if used on a 20B. The narrow boost profile is better suited for a higher-boosted lower-displacement engine.

 

I had a GT42R on my Half-Bridge 13B and am going with the same turbo on my 20B. A GT55 would be stupid. Steve Kan had a GT47R on his 20B and told me to stay with the 42R. A GT55 would be super laggy even on a 20B plus when it did spool good luck hooking up.