Turbo Garrett GT28.. which one? Options

[miguelst205]

Hi everybody from 6gc.net, the best celica forum in the net..

I'm from Paraguay, South America and I have a Toyota Celica ST205 JDM, these days I will put pictures and specifications... my English is very bad, but I will do what I can...

Here are the problems... the engine is forged, pistons and rods.. without work in the cylinder head.. the ct20b turbo shaft broke, now I'm using a ct26 to use the car.. but I want to buy a garrett ball bearing, specifically a GT28, because I want quick spool at low rpms, not a loooot of hp, good torque and a decent top end power, and is possible low or medium boost... but which one I choose??..

I'm in doubt between the GT2860RS and the GT2871R.. so, in how rpm each of these give me a good boost (like 1.2 bar), and torque??.. How much power will give me with that boost in any of these turbos??... anybody have dyno results or boost-rpm graphics to see??.. my power goal is 320 whp, because I use my car for everyday, for travel and sometimes drag race of 1/8 mile... it's a street car in conclussion...

The main thing concerning me is that will the 2871 spool a lot slower??..

Also getting new manifold or flange adaptor obviously, new downpipe (either 2.5" or 3") and injectors+electronic, etc..

I hope you can help me.. greetings, thanks in advance..

Miguel.. from Paraguay..

[jgreening]

If your goal is 320whp, gt28rs with larger A/R or cams. The 2871 is a mismatched turbo and will be VERY laggy - probably will not hit 200 ft/lbs until past 4000 rpms.

Do some searching on the 3sgte forum of mr2oc.com. Look for posts from Bruce H.

Good luck.

- Jay

This post has been edited by jgreening: Jan 6, 2009 - 3:01 PM

[Smaay]

If your goal is 320whp, gt28rs with larger A/R or cams. The 2871 is a mismatched turbo and will be VERY laggy - probably will not hit 200 ft/lbs until past 4000 rpms.


- Jay

you are not going to notice a single difference between the 28RS and the 2871. they are both excellent turbos for your application. use either one

[pittfirefighter]

i had a 2871r on my setup... get the 52 trim... full boost by 3000 rpms... great turbo... high output... easily 320 hp.... i dynoed at 300 hp at only 13 lbs, if you want a little more high end hp, the 56 trim is great too with a 3" compressor side housing intake

This post has been edited by pittfirefighter: Jan 7, 2009 - 12:46 AM

[miguelst205]

Thanks for your reply people!!.. I like the 2871, I believe that will be..

Pittfirefighter.. do you have your dyno result graphics???.. you can post it here????.. how much torque you have??..

[jgreening]

If your goal is 320whp, gt28rs with larger A/R or cams. The 2871 is a mismatched turbo and will be VERY laggy - probably will not hit 200 ft/lbs until past 4000 rpms.


- Jay

you are not going to notice a single difference between the 28RS and the 2871. they are both excellent turbos for your application. use either one

This is false. The GT28RS will hit 200ft lbs on a BPU 3sgte at about 2850 rpm and will reach 286whp at 17psi. Here is a dyno graph:



Here is a dyno of a gt2871 at 21psi on a similar setup hitting 200ft lbs at 3600 rpms and reaching 301 whp:



The suggestion that a normal person can't tell a difference of 750 rpms in spool is silly.

Jay

[lagos]

Greening... I saw a dyno run of the 2871 in person. The car hit around 280hp at something like 14psi or so. I dont see how it would need 21 psi to hit 300hp.

[jgreening]

Here is the thread if you would like to read it:

gt2871 dyno thread

[presure2]

Here is the thread if you would like to read it:

gt2871 dyno thread

meh 4 year old threads jay?
things are not quite as "grey" for any of us as they were back then, hell the recent 3071/76 tests over there should show you that!

[jgreening]

oldies but goodies. The gt2871 is a mismatched turbo. That doesn't change. If people want a BB turbo and need more flow than the gt28rs supplies, they are better off getting a gt3071 or gt3076 ---> just trying to help.

[miguelst205]

Ok, thanks for the attention guys.. I'm gonna investigate better about those turbos...

But greening, you talk about the 3071 for example.. about what rpm this turbo have a good boost and come the power???.. do you have some graphic???...

[jgreening]

Miguel, my recommendation is to do some research on mr2oc.com in the 3stge forum. You will find a wealth of information on all of these turbos. Your question about "good boost" is pretty subjective and any replies to it will be annectdotal and not real helpful for comparison sakes. The guys over at mr2oc.com generally use an arbitrary point of where the turbo crosses 200 ft lbs of torque to measure how fast it spools. Using this measure, my guess is that a properly sized gt3071 with smallest A/R will spool at about 3500 rpm on a BPU 3sgte (no special head, cam, stroking, or tuning work)---> about the same as this plot on the gt2871 but with a LOT more potential on the top end.

[miguelst205]

exactly greening... I going to do the search in that forum... but only a simple question now for you..

for example.. with the 3071 with the smallest A/R, but with a work in the head, like port and polish, 264 degree cams, adjustable cam gear, racing valves and springs, better valve lifter, etc... the spool will be given to lower rpm or not???..

[jgreening]

Generally, those modifications are designed to increase flow. In most cases, such modifications have the effect of delaying spool because air velocity decreases in lower rpms. However, a good tuner can do wonders with cams and tuning. It is possible to make a medium sized turbo spool like a small turbo with good tuning. Here is a plot of a tdo6 on 3sgte that spools as fast as tiny turbo but with 400whp:

This type of tuning takes expertise and some significant dyno time (read: $)

[miguelst205]

Ok... I'm gonna search options of price now for the GT2860RS, it's a little expensive but it's my best option in the moment...

Thanks guys for the help!!.. Greetings..

[boosted185]

aside from other people's dyno sheets, you could also look at the compressor maps for a specific turbo that your looking at getting for your car. Dyno sheets are great for reference if you have comparable mods. a compressor map for a turbo will not change per car, its directly related to the turbo itself. and also, as mentioned in a few of the above posts, if you want a qicker spool, get a smaller A/R. The smaller the A/R the quicker the spool, the larger, the more lag time you'll have, but a bigger "hit" when it does spool.

Also, if you don't know how to read a compressor map, there are some great sites that explain it in high detail.