Looking forward to going to england and get my engine this weekend.

I'm leaving tonight from oslo.

A little preview of my beauty

 

^That looks nice. Who rebuilt the engine and what did you use for the rebuild? Good luck and let us know how it goes!

 

the engine is built by Hurely Rotary in Coventry

The engine is fitted with hurley seals, 3 mm apex seals.
Street-ported engine, they promised me it will produce 400-450 hp at 15 psi boost

 

Looks good.
You should make that at at ~10 psi

 

Agreed. What turbo are you running?

 

the plan was originally to run the org seq turbos,

but after a little thinking i guess it will be a single turbo of some kind, dont know what kind of turbo yet.

Any oppinions?

 

GT42R dual ball bearing. It spools up quickly and is good to 700-800 WHP. Junk the original twins. They're too small and are good to only about 400 WHP at 15 PSI, if you can go that high. Mine would only go to 12 PSI.

 

I want a small turbo, I'm not going to take out more than about 400whp so dont need that big turbo, A smaller turbo will give better response to the engine, thats what i want since i am going to race with it

 

A small turbo will restrict the 20Bs breathing. As i see it if the engine is streetported, 500 hp is very easy to achieve with a 20B. A ported 13B can make 450 fwhp with the right set up. I would recommend at least a Holset HX40R with the biggest turbine housing or a Holset HX50. Garrett has some good turbos in GT40 or Gt42 with many compressor and turbine wheel combination to choose from. What kind of racing are you gonna do?

/Lasse

 

I would disagree with you on this. The 20B needs a bigger turbo or you'll run out of air. For example, my 20B with the stock twins made 400 WHP but couldn't get enough air above 5,500 RPMs and my engine had a very small streetport.

The GT42 I recommended has complete spool up by about 3,500 RPMs and will pull strong all the way to redline. As lasse wankel states, you can customize the 42 to suit your needs.

For racing you'll love the 20Bs low end torque. It's a very different driving experience than the 13B. With the 13B you have to rev to 5,000 or so RPMs to hit the powerband. With the 20B, you'll punch it and it will take off.

If you are concerned about the large size, you could go GT40R. Whatever you decide, get a dual ball bearing turbo. They spool quickly and you'll love it.

 

David don't jump the gun thinking small turbos will choke the engine. You have to take into consideration a turbo's flow capabilities. The stock twins were not designed to hold 400whp. Their purpose was to provide quick spool to provide extra torque ( for the much heavier Cosmo Sports sedan) in the low range and nothing more. They didn't have enough compressor and had too restrictive of an exhaust side. A turbo capable of 500 hp (like a GT35r) wont run out of air on a 20b if all he wants is 400-450rwhp. IMHO it's the ideal choice if this is his MAX power range. It makes no since to run something larger (while sacrificing response) just to have the capability to run more hp.


Norwegian_rotary the Gt35r with a large exaust A/R is the turbo that I would recommend for fast response and a really broad power band. It's what I'm going to use on my 20b if I ever boost it.

 

If all he wants is 400rwhp, why even bring up street porting? Considering how large a 20b's ports already are it would be unnecessary. The secondary ports at the point of entry are already larger than the 13brew's. A 13brew will easily hit 400rwhp on stock ports.

 

Why we are talking about street port? thats beacause i have that on the engine..

I want the smallest turbo i can get for producing about 500 hp..

this beacause of the spool up on the turbo..


What kind of turbine housing and compressor would you liked to used, and also where do you guys buy your turbos?

 

I say go with a GT35R. They allow 13b's to put down around 450rwhp. This same turbo will do the same but spool that much faster on a 20b. You should also get great response with it off boost. The midrange with this turbo could be insane. I think it's perfect for what you want. Make sure you go with a large exhaust side A/R so you don't choke to much in the top end.

 

Yes, you are correct. My experience was with the stock twins where 400 WHP was the max before the turbos ran out of air at about 5,500 RPMs. I've seen the GT35R dyno in on a 13B at 425 HP at 18 PSI so I guess it would work and offer great spool up. Most people don't consider the GT35R for the 20B so I guess I've never given it much thought.

 

Hurley street ports tend to be quite small but will easily spool a gt42 at about 3000revs. My motor is a Hurley motor, was building good boost at 3k on a gt42 giving 476rwhp at 0.9bar with stock exhaust sleeves.
Kevin

 

Aha, look like i am going for a GT40 turbo..

what options do should i have on the turbo, thinking about the exhaust turbine and the compressor..

 

Email Dave at ASE turbos (www.aseturbo.com) and ask him. He's in Australia and his email is:

ase@bigpond.net.au

He's also a rotary guy so he knows 20Bs.

 

A gt40 will be on the small side in my opinion. I'm now using a hybrid gt45 (gt42 1.22A/R hotside) and still getting good boost at low revs on the same ports but tII exhaust sleeves and very free flowing exhaust.
Kevin