Best Turbo For Autocross
compression does have a point there. . I met people that have upgraded turbos and t28bb is the best for fast spool with good horsepower numbers. its easy bolt on basically, and bigger turbos like t3's would never have a chance to spool at all in autocross. but with a fmic your going to get lag, maybe consider a bigger smic for the t25 and see what it does. 1g dsm sidemoounts are real cheap. Your best upgrade should be a lsd
I am just going to through this out, but I once heard that compressor surge wasn't as bad for BB turbos and in some cases was fine. What would happen if you were to disconnect you BOV vac. line and plug it during your runs but reconnect it when going to and from the track/daily driving.
Would that help keep the turbo spooled?
Would that help keep the turbo spooled?
Dori Dori wrote:http://www.atpturbo.com/root/r...o.gif
Remember, it's on a stock exhaust and the motor is a 1.8 so shift the graph up and over and you should get a general idea of what this turbo can do.
Is it just me, or does it really appear from all the data available that the GT28RS will have a rough time breaking 300whp? With some good tuning and cams on an SR I could see it putting out 320rwhp MAX. But it still doesn't hit full boost until somewhere just north of 4k RPM.
The GT25R looks like a much better turbo unless this is going to be on your daily driver, since anywhere above 4k(say an HPDE/road course) you're going to be MUCH better off with a GT25R. If one goes with a 0.64 A/R turbine on the GT25R then I fail to see how the DP still looks as great as it is made out to be.
Def wrote:Is it just me, or does it really appear from all the data available that the GT28RS will have a rough time breaking 300whp? With some good tuning and cams on an SR I could see it putting out 320rwhp MAX. But it still doesn't hit full boost until somewhere just north of 4k RPM.
That's on a 1.8 w/ a stock exhaust and on an AWD dyno. With a 2.0, 3in exhaust, and a rwd (or fwd) car, I don't see why it wouldn't break 300whp. You can also attribute the 'slow' spooling to the stock exaust.
The SCC car has an "open" exhaust and 2.0L of displacement and it fully spools only slightly earlier.
It just looks like the compressor has a bit of headroom over the S15 turbo, but it is seems like every example is having a hard time breaking a solid 300-310rwhp.
If you're going to be spooling at around 4.0k RPM, why not go with a GT25R and suffer a little bit slower transient response but the possibility of making 40-60rwhp more for the exact same price.
I also don't see why all the GT28RS people buy have 0.84 A/R turbine housings on them. I think the 0.64 A/R T28 turbine housing is much better suited to its compressor size and capacity. Should help spool up and make transient response even better. Although from the looks of it the 0.64 A/R Disco Potato would have even more trouble breaking the magical 300rwhp barrier.
It just looks like the compressor has a bit of headroom over the S15 turbo, but it is seems like every example is having a hard time breaking a solid 300-310rwhp.
If you're going to be spooling at around 4.0k RPM, why not go with a GT25R and suffer a little bit slower transient response but the possibility of making 40-60rwhp more for the exact same price.
I also don't see why all the GT28RS people buy have 0.84 A/R turbine housings on them. I think the 0.64 A/R T28 turbine housing is much better suited to its compressor size and capacity. Should help spool up and make transient response even better. Although from the looks of it the 0.64 A/R Disco Potato would have even more trouble breaking the magical 300rwhp barrier.
I find the T25 to be perfect for autocross. We have pretty fast courses where i go (Delta region http://www.delta-scca.org) but even in second the car has plenty of balls to dig out from 2,500 RPM...
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The T25 is a good turbo, but I compete in Street Modified, so I don't have the easiest of times in terms of opposition. And our courses are meant for low end torque. There are plenty of slow speed corners, and even in 1st gear, I fall below 3000 RPMs.
Before I splurge on a new turbo, I need to get my autocross chops up to snuff. Once I get better, the idea of a new turbo will dwindle. For me right now, it's more of a technique barrier I'm encountering.
Before I splurge on a new turbo, I need to get my autocross chops up to snuff. Once I get better, the idea of a new turbo will dwindle. For me right now, it's more of a technique barrier I'm encountering.
Def wrote:The SCC car has an "open" exhaust and 2.0L of displacement and it fully spools only slightly earlier.
It just looks like the compressor has a bit of headroom over the S15 turbo, but it is seems like every example is having a hard time breaking a solid 300-310rwhp.
If you're going to be spooling at around 4.0k RPM, why not go with a GT25R and suffer a little bit slower transient response but the possibility of making 40-60rwhp more for the exact same price.
I also don't see why all the GT28RS people buy have 0.84 A/R turbine housings on them. I think the 0.64 A/R T28 turbine housing is much better suited to its compressor size and capacity. Should help spool up and make transient response even better. Although from the looks of it the 0.64 A/R Disco Potato would have even more trouble breaking the magical 300rwhp barrier.
OMG. How could you sit there and still compare the SCC car? Obviously it's not tuned correctly or something is wrong if a 1.8ltr is spooling faster and making more peak power on a stock exhauset and AWD. Ahhhh, whatever...:rolleyes
Dori Dori wrote:OMG. How could you sit there and still compare the SCC car? Obviously it's not tuned correctly or something is wrong if a 1.8ltr is spooling faster and making more peak power on a stock exhauset and AWD. Ahhhh, whatever...:rolleyes
First of all, drop the smug attitude.
Secondly, I fail to see how "not tuned correctly or something" can make THAT large of a difference in spool. Ignition timing and to a smaller degree AFR and cam timing/specs are the only factors that are remotely easy to alter.
A more simple explanation is that the AWD dyno probably loads up the 1.8T more than a lower inertia two wheel drive dyno, therefore skewing the results more in its favor for spool time.
Honestly, a 0.86 A/R T28 backside with the high flowing GT series wheel is too much turbine for a 2 liter motor with that "small" of a compressor.
"First off", :moon :fruit
"Secondly", I fail to see what you're trying to prove. It's obvious that your comments about an SR needing cams to make 320 on that turbo are false (unless you think two less wheels to spin, an open exhaust, and more displacement can't yield 20hp). I don't understand your spool argument...a GT28rs spools inline with the stock t25 up until the t25 stops making power...then the GT28rs just keeps rising (and fast). What do you expect? 21psi by 3k?
As for your comments about dyno load and awd, since we don't know where the load application was set on either dyno, your argument is purely hypothetical.
"Secondly", I fail to see what you're trying to prove. It's obvious that your comments about an SR needing cams to make 320 on that turbo are false (unless you think two less wheels to spin, an open exhaust, and more displacement can't yield 20hp). I don't understand your spool argument...a GT28rs spools inline with the stock t25 up until the t25 stops making power...then the GT28rs just keeps rising (and fast). What do you expect? 21psi by 3k?
As for your comments about dyno load and awd, since we don't know where the load application was set on either dyno, your argument is purely hypothetical.
Dori Dori wrote:"First off", :moon :fruit
"Secondly", I fail to see what you're trying to prove. It's obvious that your comments about an SR needing cams to make 320 on that turbo are false (unless you think two less wheels to spin, an open exhaust, and more displacement can't yield 20hp). I don't understand your spool argument...a GT28rs spools inline with the stock t25 up until the t25 stops making power...then the GT28rs just keeps rising (and fast). What do you expect? 21psi by 3k?
As for your comments about dyno load and awd, since we don't know where the load application was set on either dyno, your argument is purely hypothetical.
I'm just talking "cars" here and you come at me with such a condescending attitude that reeks of Internet E-thug. That's why you got the attitude comment, so I'm glad to see you actually gave it enough thought to throw out a couple of "cute" smilies. I hope you would not presume to talk to me in the same manner if we were hanging out around a few cars and talking about this very same topic...
About the cams and 320hp, I never said it was needed, but it's quite easy to see that a mild cam upgrade does the SR20DET some good. The head flows really well, but the cams are pretty timid. Higher flowrates will lead to higher volumetric efficiency at high RPMs with all things being equal, so it can help a compressor approach its theoretical limits up top.
The GT28RS does spool up nicely for a turbo of its size, but it just doesn't seem to really have that much much in the tank over an S15 turbo, when the specs suggest it should easily surpass it. Heck, people here are making over 250rwhp regularly with a T25 and bolt-ons. A T04B compressor with a new pimp GT series wheel in it to me would lead to more than what I've seen of this turbo.
As for me speculating, I'd say that's exactly what you're doing when you talk about what the GT28RS equipped 1.8T can possibly do if...then if...and if... etc. But that's ok, that's what car talk on the internet consists of - speculation. So please don't use that point to try to win an "argument" that is just idle talk.
:rolleyes I'm not going to go research specs on different dynos and guess who's using what and how they have them calibrated. Because then when we're done with that, we'll have to compare and contrast thousands of other aspects of the cars/air/elevation/ect. I have better things to do with my time. Besides, spool is the main concern here and I still don't understand what you want...it spools as fast as a stock T25 and is 300+whp capable. We know that. You like the GT25r better? Cool.
Well since you don't "calibrate" an inertial dyno, and I knew that stuff off the top of my head, I guess you're just graciously "giving me" that one.
I don't "like" any turbo better than another. There is always a best match(or compromise) for a given application.
I'm just idly talking about the potential of this turbo on the SR, but you seem to be having a hard time seeing that, or at least treating my posts accordingly.
Frankly, the only reason why I started posting in this thread is that I'm pretty interested in seeing how the 0.64 A/R turbine GT28RS would perform. Unfortunately, there is always an *** on every forum that rates validity and experience on post count. Or just can't get over themselves...
I don't "like" any turbo better than another. There is always a best match(or compromise) for a given application.
I'm just idly talking about the potential of this turbo on the SR, but you seem to be having a hard time seeing that, or at least treating my posts accordingly.
Frankly, the only reason why I started posting in this thread is that I'm pretty interested in seeing how the 0.64 A/R turbine GT28RS would perform. Unfortunately, there is always an *** on every forum that rates validity and experience on post count. Or just can't get over themselves...
You know what, my initial comments were in no way 'smug'…up until you started mentioning the SCC car...which IMHO and anyone else's w/ 1/2 a brain, is a bad candidate for comparison. It's also a subject that has been beaten to death and shows your lack of research. The only reason to even look at it is for spool characteristic...and they show how fast the DP does spool. I never mentioned post counts; they don't matter to me. I digress; well, I never did any name calling or bashing and you have the nerve to call me an E-thug in one sentence and an *** in another. Honestly, I think you just have a hard time taking criticism... you're probably an engineer or something so it's like a straight shot to the nutts when anyone opposes your ideas.
Oh, and according to this page ( http://www.awe-tuning.com/page...AQ=22 ), load application is adjustable on their dyno and a Dynojet to lessen the load at the wheels, effectively lowering inertia, right?
As for your curiosity about a GT28rs w/ a .64a/r, don't bother because AFAIK, they don't exist.
Oh, and according to this page ( http://www.awe-tuning.com/page...AQ=22 ), load application is adjustable on their dyno and a Dynojet to lessen the load at the wheels, effectively lowering inertia, right?
As for your curiosity about a GT28rs w/ a .64a/r, don't bother because AFAIK, they don't exist.
Anyways, when you two are done massaging each other's nuts.
I would reccomend an FPBig28 (T28 wheel in a T25 housing) http://www.forcedperformance.com. I got mine from HT for $775 + $75core which is awesome because I didn't have to send my turbo off. I am extremely impressed with this turbo already and I haven't even close to maxed it out. Full boost just about the same as my old T25 and then holds to redline. And since it's a T25 housing, it bolts up just like stock.
Shaun on 240sxforums awhile ago made 345RWHP with one at 21psi with only the usual bolt-on engine mods.
I would reccomend an FPBig28 (T28 wheel in a T25 housing) http://www.forcedperformance.com. I got mine from HT for $775 + $75core which is awesome because I didn't have to send my turbo off. I am extremely impressed with this turbo already and I haven't even close to maxed it out. Full boost just about the same as my old T25 and then holds to redline. And since it's a T25 housing, it bolts up just like stock.
Shaun on 240sxforums awhile ago made 345RWHP with one at 21psi with only the usual bolt-on engine mods.
Here it is... This car belongs to Aubrey not Shaun (used to be a mod on 240sxforums). You can see a T25/T3 hybrid in red and the FPBig28 in blue. I was little off, the T25/T3 made 345whp at one point, but the power number for the Big28 below are still impressive. This was all done with stock manifold too, so a better flowing manifold and o2 housing would definitely help those numbers.
Power:325rwhp342rwtq
Engine:SR20DET, FP Big28, JWT ECU, APEXi 740cc Injectors, Z32 MAF, Greddy FMIC, Greddy Type-S BOV, Greddy 80mm Downpipe,3” Test Pipe, Apexi N1 3” Catback, Walbro 255lph Fuel Pump.
Here is a track slip for anyone interested.
12.3 @ 117 mph w/ a 2.0 60-foot
Power:325rwhp342rwtq
Engine:SR20DET, FP Big28, JWT ECU, APEXi 740cc Injectors, Z32 MAF, Greddy FMIC, Greddy Type-S BOV, Greddy 80mm Downpipe,3” Test Pipe, Apexi N1 3” Catback, Walbro 255lph Fuel Pump.
Here is a track slip for anyone interested.
12.3 @ 117 mph w/ a 2.0 60-foot