What turbo for 9:1 compression, GTX28/30?

[Dipstik-sportech]

Originally Posted by Synack

Honestly I'll probably never go back to Precision.

Were your results on 9:1 compression?

9.5

[AZFA20]

For what it's worth, I'm personally a huge fan of the gtx28 series as well.

[Andre da gr8]

Originally Posted by Manji

I'm not saying that high comp is bad. I'm saying too many people are looking at their turbo builds through NA-knowledge-tinted sunglasses.

nice saying

[cdrazic93]

Originally Posted by Manji

I'd run more than 9.0:1 as well, but it's not like it'll be a dog of he does.

Static compression is over emphasised on here when it comes to turbo builds.

Unfortunately the masses of enthusiasts understand static compression whereas dynamic compression isn't as well known, or as well understood.

Originally Posted by Synack

That's about 15psi, are you serious? That's crazy.

Yea you'll see a lot of PSI the lower the comp for pump gas. Technically you could run more than that if you wanted, but you'd be going past 400whp. Since the GTX28 is a relatively small turbo, I wanna say boost will be there at 2900-3000 rpm. Most people think that low comp will be bad response, but the response is offset from the amount of boost pushed. To make it better I would reccomend a twin scroll manny if they have one for the 28

[Synack]

Originally Posted by cdrazic93

Unfortunately the masses of enthusiasts understand static compression whereas dynamic compression isn't as well known, or as well understood.



Yea you'll see a lot of PSI the lower the comp for pump gas.

I mean that's crazy low! I've been running 20psi so far! Although I can't really tell but it might be on a conservative tune. I'd be very happy with 15psi.

[cdrazic93]

Originally Posted by Synack

I mean that's crazy low! I've been running 20psi so far! Although I can't really tell but it might be on a conservative tune. I'd be very happy with 15psi.

I'm not sure about 15 psi though... @woode made 412 whp on 93 on stock CR (I think) with 21 psi

[King Tut]

Originally Posted by Synack

Trying to decide which turbo to go with to get 400whp with 93 gas and meth BUT with 9:1 compression.
Let's not make this a discussion about why my compression is so low!

400whp on 93 is my ultimate goal, but of course I want the best possible dyno curve and response. I'm upgrading from a Precision that has some lag to it.
I do not plan on getting any more power out of it so I could care less about room for upgrading. I'm also trying to do this without E85.
All I know is that my turbo creates a lot of heat at 20psi and I'm trying to get something more efficient. So I want a GTX series turbo.

You still remembering your drive of my car? Remember that was only a lowly GT2871R.

[woode]

Originally Posted by cdrazic93

I'm not sure about 15 psi though... @woode made 412 whp on 93 on stock CR (I think) with 21 psi

Sure did. Although, I think the OP's goals are quite a bit different. I wouldn't take my current setup to a track - I think heat would kill it.

[King Tut]

Originally Posted by cdrazic93

@woode made 412 whp on 93 on stock CR (I think) with 21 psi

I like to think of him as being an outlier.

[cdrazic93]

Originally Posted by woode

Sure did. Although, I think the OP's goals are quite a bit different. I wouldn't take my current setup to a track - I think heat would kill it.

So 12.5:1 CR with 21 psi on 93 pump gas only made 412 whp...yeah you'll need more than 15 psi

[Synack]

Originally Posted by cdrazic93

So 12.5:1 CR with 21 psi on 93 pump gas only made 412 whp...yeah you'll need more than 15 psi

Could be a conservative tune. I've seen people with about the same psi making over 500whp.

[Synack]

Originally Posted by King Tut

You still remembering your drive of my car? Remember that was only a lowly GT2871R.

Andddd now it's time for a GTX2867R!

How much did you sell yours for again?

[King Tut]

Originally Posted by Synack

Andddd now it's time for a GTX2867R!

How much did you sell yours for again?

$32.5k. My M3 is sold, and it is time to build another turbo 4 cylinder.

[woode]

Originally Posted by cdrazic93

So 12.5:1 CR with 21 psi on 93 pump gas only made 412 whp...yeah you'll need more than 15 psi

Timing. Pump gas with that high of CR and that much boost needs more timing to be pulled to keep knock away, which results in more heat. A lower CR could surely run less boost and more timing and make similar numbers more safely even.

There are so many different approaches to tuning and engine building.. everything is a compromise.