Not sure if you guys have seen this before...it's a great source of info. on Garrett's turbo lineup, including compressor maps too!!

http://www.turbobygarrett.com/turbobygarre...ers.html#medium

 

Just to add to this thread, here are the maps for the GT30 and GT35 turbos. Purple dots are 8psi and the red dots are 15psi.

 

[QUOTE=Scorpion,Jan 3 2006, 10:02 AM] Just to add to this thread, here are the maps for the GT30 and GT35 turbos.

 

The Dots are at 9000, when plotting it's basicly a straight line across. The dots may not be "perfect" but They are close enough to aid in a turbo selection. I use a niftly little program that calculates this all. VE being that X factor that I have to guess at. I have heard everything from 100%-140%. I use 112% for all my calculations.

 

Your Ve of 112% is about spot on (in fact the Ve is > 100 % from ~ 6250rpm onwards { SAE Technical paper 2000-01-0670 Yutaka Otobe, Hiroshi Kawaguchi and Hideo Ueshima Honda R&D Co., Ltd. Page 8 })

I still feel that the lb/min is a bit low, you need roughly 1 lb/min per 10 HP

 

I could be wrong about this. I'd be lying if I said I fully understood it. But aren't we supposed to plot the injector flow rate corresponding to our horsepower goal. I believe it is 44 lb/min for 400 crank hp and 55lb/min for 500 crank hp. If that's the case, then 500 hp would not be attainable with the 3071R since it lies completely off the map.

 

Where can I get a copy of this SAE paper? Could you email me a softcopy? It looks like an interesting read.

I was using 100% VE in my calculations and the result didn't look right. I think that's where I screwed up. It's incredible the F20C can have a >100% VE. That's awesome for a normally aspirated engine. I guess Formula 1 does have it's pay backs!

 

There are a lot of factors that determine the amount of air flow needed to hit a certain HP mark. If your turbo puts out 10hp per psi, then you will nedd less air than a setup that only puts out 8hp per psi. Look around the forums and you'll see that kits very on hp per psi greatly. It's not just how efficiant the turbo is, but also the maifold, intercooler and piping. Garrett recommends using a 10hp per psi for calculating lb/min on there turbos. Which means if I wanted 400hp (crank) then I'd need 40 lb/min. The problem with this is that because the lovefab I have is so efficant, I make over 310whp (370bhp) at around 30 lb/min.

Edit: I just noticed you said injector flow rate. Taht really has nothing to do with what we are taking about. Of course it's important to have proper fueling, but that has nothing to do with finding the proper turbo for your power goals.

 

You can get it from SAE

here is the link Document Number: 2000-01-0670

It's US$ 12 for non members to download a DRM protected copy.

 

Sorry...what I meant to say was airflow rate. It was late when I was typing last night. But thanks for the explanation.