Which turbo should i get?

[tvmendoza]

Hello everyone, this is my third year with my S14 and this also my 2nd year with a ka-t this is my previews setup:

SSAC t3/t4 manifoldebay t3/t4 turbo3" downpipe3" exahustSAFC 2370cc inyectorsz32 maffmic turbonetics wastegate at 7 psiwalbro fuel pump 255RFL bov

This setup made 240 whp at 7 psi with the s14 maf, i never had money again to change anything until now. I am doing an intership far away home and i did not bring the car so i sold the turbo and mani and i am buying everything back to get a better setup. By the way my car is totally rebuilt with forged pistons, everything else is stock.

This is what i bought already:IAP Manifold and downpipe850cc denso injectorsTuned S13 ECU from Ebay's tuners, hope it works wellMSD 6As14 to s13 ecu harness(still have not arrived if you have one for sale let me know)

I am missing the turbo but i am not sure which one to get, also if you can point me what else should i get.

Turbos options(i do not want to expend more of 800dlls).

Garrett GT37 550-hp $710.00 Is it too big?Garrett GT32 420-hp $599.00 too small?Garrett GT35 600-hp $750.00 good?Garrett T3/60-1 it says 575 whp $650

I will love to have the gt33 ams turbo but that is over my budget.

What do you think? I will use this car just for having fun on the track, and i want to run this motor until blows and then start a fully build engine.Please let me know any suggestionThanksTona

[C-Kwik]

You should list your priorities (HP/boost levels, and what kind of response or lack thereof is acceptable.

As far as the 60-1, you should look at this thread before even thinking about that...

zerothread/264264

[tvmendoza]

Well, my power goals are around the 450whp to 500whp once i have a build engine. I am not sure how much will hold just with pistons. Here is a little bit more information about the t3/60-1, since it is a t3 inlet i am not sure if it still qualifies as a straight t3.

flow: 61 lbs/min 781cfm

.70 A/R housing60-1 TRIM wheelTURBINE SPECS:T3.48 A/R housing/ .63 a/r or .82HIGH FLOW 76 TRIM stg 3 wheel

I think we are not talking about the same turbo as turbo2nr.

What i want and it might not be possible is have a turbo that i could use now and that could use once i go crazy.

[scheffler]

you need to look at the ebay ecu and see if it was programed for a certain turbo or cfm rate if it was I would recomend getting that turbo or one that matches cfm or close to it, other wise you might have problems. If it doesn't list one than get what you want and will meet your goals

[C-Kwik]

Well, my power goals are around the 450whp to 500whp once i have a build engine. I am not sure how much will hold just with pistons. Here is a little bit more information about the t3/60-1, since it is a t3 inlet i am not sure if it still qualifies as a straight t3.

flow: 61 lbs/min 781cfm

.70 A/R housing60-1 TRIM wheelTURBINE SPECS:T3.48 A/R housing/ .63 a/r or .82HIGH FLOW 76 TRIM stg 3 wheel

I think we are not talking about the same turbo as turbo2nr.

What i want and it might not be possible is have a turbo that i could use now and that could use once i go crazy.

Have you looked and compared the maps? The 60-1 and 62-1 are fairly similar, especially when you plot out the KA's airflow/boost mapping on it. I mention that in one of my last posts in that thread. Just about everything mentioned there applies to the 60-1 on the KA.

Simply looking at the power rating of a turbo is NOT the proper way to choose a compressor for a motor. In fact, the peak airflow rating of a turbo is not easy to reach if a turbo is sized on the larger end for the motor you will be installing it on. The 60-1 and 62-1 was designed for engines that can pump a lot of air. Large V-6's and small V-8's are better matches for this turbo.

As for the turbos you mention, none really are a great match if you're going to be increasing boost over time as you upgrade the motor. I'd seriously consider the T04E 50 trim if that's what you plan to do as the 50 trim is quite flexible. If I had to choose from your list though, I'd go with a GT37.

[tvmendoza]

Well, i have looked the t04E also, but i tought it might be too small for what i need but if you think that is enough i will search prices and compare. Do you think that the gt37 would not have the same problem than the 60-1? What about the gt32 and gt35 which one will give more power at a faster time.

I am sorry for asking this kind of questions, but i have a couple of days triying to read compressor maps and i still do not get it(i read the "how to read compressor maps") and i still dont get it. Thanks for pointing out that the 60-1 is not for our motor but what about the other 3...

[C-Kwik]

If you have a goal approaching 450-500 HP, then the GT32 and GT 3571 is going to run out of steam well before you get there. The GT 3582 has the headroom, but the surgeline shape may be a bit concerning. I'd have to have a better idea of the spool up properties to make a good assessment, though.

The GT3771 and GT3782 are both possible candidates, with the 71 mm version performing better at lower boost levels (up to a PR of about 2) and the 82 mm performing better at the higher boost levels (starting from about 2.5 PR). If I were to choose, the 82mm would be the better choice of the two if you're serious about the power levels you are trying to reach. The 82 mm is fairly evenly matched with the 50 Trim T04E at 2.5 PR.

As for reading a compressor map, you might try and let us know what is not clear so we can help you understand. I'd love to help, but short of explaining everything again, i wouldn't know where to start...

[tvmendoza]

Assuming the following(from Checkered-Member) :

At 6000 rpm the KA flows 26lb/minAt 3500 rpm the KA flows 15lb/min and you hit full boost at this level.PR = (14.7 + psi)/14.7= Air Flow

HAving that i plot the following at 20 PSI:

PR = 2.36 = (14.7 + )/14.7



-That means that at 3500 RPM (yellow dot)i am going to be outside of the chart which i assume that means that i have not reach boost.

-At 6000 RPM(green dot) i am going to be at 74% efficiency of the turbo which is good or bad?

Let me know if i am totally confused or what is going on, i think one of my problems is that i am not sure what kind of information i am going to extract from a compressor map.

[C-Kwik]

I'm not sure where you're pulling the numbers from, but 26 lbs/min would be extremely low for a 2.36 pressure ratio. based on someone else's calculations you'ld likely be closer to about 43 lbs/minute at redline at a pressure ratio of 2.36.

You have to realize that as boost increases, airflow proportionately increases as well. A pressure ratio of 1 is essentially no boost. A pressure ratio of 2 theoretically doubles the airflow of the NA motor.

As for being to the left of the map, that left edge is what is referred to as the surge line. Anytime you're operating a turbo in that range, you are operating in surge. You definitely do not want to be there.

[tvmendoza]

I got the info from this thread:

zerothread?id=59168

on the first post.

Then i am totally confused where can i get the lbs/min of the ka?

[C-Kwik]

His figures are all based on 9 psi of air which is a pressure ratio of 1.61.

Look about 3/4 of the way down that page. spitz7985 and trunkmonkey both calculated the normally aspirated flow rates. Each used a different assumed volumetric efficiency, so the numbers are slightly off from each other and the RPM points they made their calculations at are aslo a bit different, but likely close enough to estimate where you'll be on the compressor map. Take those NA numbers and mulitply each by the pressure ratio you want to map out. If you take trunkmonkey's number at redline, at the 2.36 PR, you'll have about 40 lbs/min which would place you right at the tail end of the peak efficiency island.

Hope that makes more sense...