Honestly, you'd have to try one first! Difficult I know.
We've built several using the 35 billets, and believe me, you'd be amazed at how flexible they are considering we're talking 500 bhp and beyond.

 

Cheers Alan! That us some skilled engineering, what I am interested in is if 550plus bhp is a realistic goal for a 2.1 stroker running either of these turbos? Or would 500bhp be a far more reasonable estimation for a car that wants to have a degree of reliability?

 

Hi Ryan Im also looking forward to your mapping results as you piped me to this turbo and it was my first option Harry up

 

Also guy if you read my spec mines only a 2.0ltr although it full forged and lots of head work and mad piper cams nos is on the future shopping list

 

Well, this is where it gets down to the nitty gritty.
As far as the engine is concerned, it isn't a turbo issue, it's only about cylinder fill being adequate for the purpose of power production.
It helps to bear in mind what's happening. As far as the engine is concerned, the actual output is of no consequence, assuming that the infrastructure can stick what you're asking of it.

What makes an engine "go pop"?
Usually, it's some secondary cause, such as inadequate or incorrect fuelling, poor or over ambitious ignition or boost control, or any one of a dozen reasons linked to bad design or poor maintenance. I'd say missing a gear is pretty much up there as well, along with other driver induced maladies.
A well put together Impreza engine with nice clean internals will put up with a lot, considering the fact that they aren't a precision instrument, from a purely engineering viewpoint. We have to carry out corrective machining all the time, just to fix factory issues.

We built one 2.1 going back several years ago that suffered from "Mission Creep". This is where we build an engine of a particular spec, that then ends up being pushed well beyond that target. We only used basic forged rods and pistons, but it ended up running well over 600 bhp, and carried on doing that, despite severe provocation on road and track until only recently. Eventually, it decided it didn't want to be doing that any more, but that wasn't a fault of the motor itself, and only after it actually ended up giving well over 700 bhp!
That particular car now runs another of our 2.1's.

There is no reason why 550 bhp should be more of an issue than 500, assuming you have everything you need to operate at that level in terms of quality of component and specification. The big difficulty comes in when you're asked to provide a finished product that has vital parts missing on grounds of cost.
Given the option, I'd always want to "turn the wick down" from what is actually possible to a level where it's slightly more forgiving, considering what some people do with them! It's like climbing Everest. Sooner or later, you end up in the "Death Zone"

We built the engine for Paul Doyle's Time Attack car. He's used it for a good number of meetings since, running at around 800 bhp using a Nitrous shot.
The car is well put together, and he has a great team back up. As far as I'm concerned, as an engine builder, that's as far as we're likely to go in terms of proving that we can cut it. If a race engine lasts for one race, that's as much as anybody can expect, although Paul hasn't been off the podium since it went in.

As to your 500/550 question, you can either go for a more relaxed output from the GT35 (more top end for less boost) or run the S206 up with a touch of methanol and a bit more boost. Your choice!

 

I think the only reason for wanting a 35 over a 30 on a 2ltr or 2.1ltr is pure ***** waving.

If you drove both in a blindfold test the 30 would be better in probably every situation other than a drag only car.

 

Agreed Frayz, depending on how the car drives after VVT is sorted I may switch down to a billet 30 too

 

Been there, done that on a 2.35 and swapped for a 30.

35 is an amazing turbo but unless it's a drag specific car is complete over kill IMO. 30 with a .63 is a much better option, especially on a 2.1

 

Mike's car runs a GT30 billet, we like that one too!
Horses for courses..

 

I've a 2.5 on a stock 35 that isn't pushed making 573/510. Very tempted to swap to the billet 30 that should do that and come on even quicker.

2.5 + billet 30 has got to be brutal!!

 

I think I'm a bit old to wave my ***** especially in puplic but for me it's driving a stripped out type r with big hp on track of course although its costing me a fortune as you guys well no that.But to get the same feeling on a production car would cost 10 times as much and even then I'm not sure it would be as good. after all of your comments I feel is got to be a billet 30 so now what the difference between the housings .63 and I think its a .83

 

It will spool earlier on a .63 housing but make a little more top end on a .82

A .82 will make it slightly more laggy tho and IMO Thr whole point of a 30 is the benefits of improved spool

You'd have to have some car and be some driver to max out a 30 on track to the point where you needed to upgrade turbo's.

John Stevenson is a seriously good pilot and the 30 is good enough for him.

 

.63 is the only housing to get for billet 30.. .0.82 gives a lil more top end but at the sacrifice of a lot of spool

 

The 0.82 housing from my experience on a 2.1 makes the turbo a little unbalanced and laggier than it needs to be, stick with the 0.63

 

A stripped out type R...

A 30 will do 600 if pushed, 550 adequately. That in a type R and you'll have ample and flexibility to use it too.

 

This is a huge learning curve for me and I thank you all for not only your opinions but for you to share your experiences I want to use my car for track racing sprints maybe time attack but I think I should learn to walk first the gt30.63 billet looks to be my best option

 

I have 600bhp in a full weight type r, will be mental in a stripped out one

 

That's the problem of course, it's all a matter of opinion which is owner specific.
One of the 2.1 strokers we're running in at the moment is going to Gibraltar when it's finished. It's a track day car.
With the extra heat out there and it's intended use, being able to run a GT35 at .2 bar less than a GT30 to achieve the same power is very desirable.
The fact that it takes a little longer to get there is barely worth mentioning.

 

Oh yes I forgot to say in the future I have on my shelf in the garage a ej22 and big port jdm avec heads

 

I can't wait till next year it's going to be mental

 

Deffo buy a 35 now then, it'll save swapping the 30 for it later

 

Good idea but don't no how long it'll be before that one gets done and want to enjoy this one first remembering MJ this is one of your engines after all

 

Surely with the added heat out there a 30 would be a better choice as the heat generated from the bigger turbo would surely exceed the .2 bar less you mentioned.

I had charge temp issues when running the 35 but none since swapping to a 30.

As you said, each to their own. Personally I think a 35 on a 2.1 isn't the most compatible or optimum combination.

 

There seems to be a ready market for used turbos, so I don't suppose it matters. We're swopping them around all the time, on occasion having several cars lined up while we play "pass the turbo"

 

I would have thought quite the opposite Matt. The 35 shouldn't be working as hard as the 30 at the same power level so should put less heat into the ACT.

 

Matt bare in mind you also changed to a more efficient intercooler at the same time but agree a billet 30 on a 2.1 would be my preferred combination

 

Point taken Frayz.

Both are extremely good turbo's. Maybe I prefer the 30 cos I couldn't handle the car with a 35 on lol

Nice repair job on those heads btw

 

One thing I noticed you all talk about 2.1 I brought a 2.0 have I made another **** up

 

Thanks, done a few now. Costly process, but nothing like as costly as buying new heads especially when they have already been worked.

 

Not at all, it's just a case of getting more out of a full build, given the option.