I hate always seeing peeps on the board thinking cuz you can run 10psi of boost on the HRC kit you can do it as well on the Star kit and make the same power and all the fuel setting will be the same! There are some differences between the two turbo's that most everyone seems to over look. First of all they are two totally different size turbo's. A S16G Flows say 575cfm, a S20G flows 680cfm, and a T3-T4 Flows say 785cfm. Can you see the size difference?? Now if you take two of the idenical engine setups and throw 10psi of boost with the S16G at one and 10psi from a T3-T4 at the other, your gonna see two totally different HP curves and peak numbers. Just for instance a T3-T4 with 10psi on the dyno may make 250FWHP and a S16G with 10psi may make around say 200FWHP(that's a 50HP difference at the SAME boost level!). so with that in mind both turbo's make totally different power at the same boost levels. Like a T3-T4 can make More power on pump gas then a S16g or even a S20G, the reason a T3-T4 can make more power on pump gas than is S16g or even a S20g is because the T3-T4 has less backpressure, less heat which gives lower egt's and less detonation. So to some people that makes the T3-T4 the turbo of choice.....it's still a very streetable turbo and makes good clean power. So these are just a few words of wisdom for those of you who think that you have to match boost levels between the two kits to make the same power. Does my babbling on make sense to anyone?

P.S. some of these #'s I gave may not be exact, there pretty much just examples and if anyone has anything else to add or say, do it up ;-)

Makes perfect sense and i have been saying this for a while now, to those who'll listen. it's common sense.

Do you have any dyno charts at 10PSI on your STAR? I'm curious to see the hp/torque curves.

...making the star kit faster when driving in a straight line, shifting upwards only.

:-)

I broke my tires loose at 90MPH Thursday, top of third gear. 10PSI. That's one good thing about the STAR kit.. It's got great top end. Could use a better FMIC and piping design.. but it's got a nice turbo for >4000RPM.

Wow it's funny how the HRC instructions are so detailed and professional, and the star instructions look like they wrote em in an hour.

Faster spool up on the s16g was always why i liked hrc better. I guess in the end it's all in preference.

hope this post wasn't posted cuz of my other post on turbo tech.. i didn't mean to make it a bust on star.. shoulda edited it better, my bads if i gave the wrong impression.

>Faster spool up on the s16g was always why i liked hrc
>better. I guess in the end it's all in preference.

This is also one of the reasons i always wished i'd bought an HRC kit. Now that i'm built and running more boost.. i'm happy with what i ahve. I still very much appreciate the engineering of HRC's kits, but my STAR setup has top end like a freight train has good brakes. It effin rocks.

I have been thinking about this and this is what I came up with....

Lets say the t3/t4 turbo is making 10 psi and the s16g turbo is making 10psi also. Isnt psi messured at the intake manifold. If it is, then 10psi should be the same wheather its from the t3/t4 or the s16g. Isnt 10psi just 10psi. It is a measurement of pressure. Lets say you have a super air compressor that fills tires fast and then you have shitty air compressor that plugs into your lighter. Both compressors will be able to put 10psi of pressure into a tire. But the bigger compressor will be able to put more presure in. The way I look at it, I think the t3/t4 is capable of more boost than the s16g but the s16g is very capable of 23 psi and who needs more than that. The s16g spools faster also. As you can see I have a s16g so I like it a lot;-). But when you have 10 psi at the intake manifold from either turbo I believe it is the same no matter where or how it got there. The only deifference is the speed at which it gets there and the output capability. Am I thinking correctly?

I agree with you Dave. Yes the T3/T4 flows more cfm's, but that only helps you if you have large ic pipes and a bored out tb etc... I can't see how 10 psi will be any different from a T3/T4 than a S16G without having larger openings between the turbo and the cylinders to flow more air.

so, with that situation, you could put,for instance, a T-88 turbo on your eclipse, run 10psi on it, and not expect any HP gain over a 16g? i dont understand that concept.

Dave, read what Greg said "the reason a T3-T4 can make more power on pump gas than is S16g or even a S20g is because the T3-T4 has less backpressure, less heat which gives lower egt's and less detonation."

Yes 10 psi is 10 psi but you have to remember the other factors.

Right. Everything Greg stated is correct. And in some sense, as others have noted, 10 psi is 10 psi. No doubt about it. But, (and this is a very big "but") that 10 psi with a T03/04 turbo, depending on its sizing b/c there are a LOT of T03/04 hybrids out there, produces its 10 psi at a much lower temperature than would a S16g. That means it comes on with more power without requiring additional cooling. We have to remember that power in a horespower sense exists on so many more planes than just displacement, boost and rpm. We also have to consider the very important variable of _temperature_. That's why we all go to such troubles with intercoolers, CAI's, more fuel and such.

This isn't to say that this additional power of the T03/04 doesn't come with tradeoffs. As Dino and I constantly preach, you need to factor in the additional power the Garrett turbo pushes when figuring out the amount of fuel you need to supply. You can't merely apply the same equations from a S16g as you would to a T03/04. Another tradeoff, as Dino has noted is lag. I like where the S16g's power comes on. I wouldn't mind if it were a tad sooner, but all in all, I'm very happy with it. I do admit that when driving my brother's GS-T with a T25, the throttle response is amazing. There simply isn't any lag present. Push throttle, full spool, turbo thrust, and that's it. For around town driving, it's unparalleled when measuring the "fun" factor.

Good post Greg. I think many of us have been preaching the same thing for a long while, but it's never something that can be emphasized enough to dispel any misinformation that can seep into people's minds. :-)

>so, with that situation, you could put,for instance, a T-88
>turbo on your eclipse, run 10psi on it, and not expect any
>HP gain over a 16g? i dont understand that concept.


EXACTLY!! That could not have been put any better. Like for an example I saw Brent Rau Lay down 650WHP off the bottle with a T88 Turbo and 30psi. Then I saw a 99GSX make 450WHP and he was running 30psi on a T3-T4. Dave_FL: can you see the difference now??

the two cars you are talking about are totaly different engines. One is a 2 liter V4 and the other a 3 liter V6. But I agree with you somewhat. I think Jason made a good point about the heat that a turbo makes. I didnt think about the heat factor. The t3/t4 probably does make a significant lower amount of heat due to its larger size therefore producing more hp at the same boost pressure. So I guess your right Greg.

I like posts like this :-). I find this very interesting.

Well here's the only comparison I've actually seen a dyno graph of with a larger turbo being installed. a T3 with a .48 turbine AR put down 329 @ 15lbs of boost (this a B16A honda but same princible). Switching to a T3 with .63 AR and no further changes power went to 342 @ the same boost level. On the graph it made about 12hp more from 4700 to redline while from 2-4.7K rpm the .48 T3 made about 10hp more. So 10psi is not 10psi with any turbo. The gain was attributed to the decrease in backpressure from the larger turbine housing not heat and all that other sh*t usually associated with bigger turbo's making more power (the compressor size was the same so the gains came from the exhaust side only). I think its safe to assume reasonable tuned the Star turbo should be putting out more top end while a hahn kit should be making more below say 5K rpm or so. From personal experience I'd say the Star feels good from 3500-5000rpm and from 5000rpm up is a monster. I too broke the tires loose at 90+ on the 3-4 shift @ 10psi with a notorious CF clutch (I was on 14" but shit breaking the tires loose at 90 is a feat regardless). If you get caught in the wrong gear 4cyl probes will be kicking your ass. Despite the high rpm the turbo really kicks in its easy enough to stay in the fat part of the curve. Launch at 3000rpm and short shift 1rst and it was all good.

I can compare the two turbo's but on different cars and not at 10psi. First off let me say that I don't like the T3/T4 at all, it has way too much lag for a street car. I remeber when I was first thinking about buying a kit for my 96ESi I really considered the Star kit for the "better" turbo, because I thought I needed the bigger turbo. Now I see I was way off, and here's why. I now have a 96NT with a HRC S16G, FMIC, 3" exhaust, AFC and running 5-6psi. Now on the other hand I have a heavily modified 92 GVR4 with a T3/T4, 30x12x2.5" FMIC, 3" turbo back exhaust, VPC, GCC...... Now having said this the Galant runs 18-19psi on pump gas and really pulls, but there is no real kick until 14psi after that your thrown back in the seat. Bottom line is the Talon feels stronger in the early stages of boost then the Galant of course, but from my point of view I don't see the T3/T4 being much fun unless you can run high boost levels. I'd love to hear from someone who has driven both turbos on a 2GNT to see how they really stack up when run on the same motor at the same boost. Dyno numbers, I have no doubt the T3/T4 will make more power the the S16G at the same boost levels but my seat of the pants dyno says the S16G will feel stronger at that boost level because you'll be waiting forever for the T3/T4 to spool. I imagine the ball bearing option would be a totally different story but I don't have one, so there's my two cents.

I now have a 96NT with a HRC
>S16G, FMIC, 3" exhaust, AFC and running 5-6psi. Now on the
>other hand I have a heavily modified 92 GVR4 with a T3/T4,
>30x12x2.5" FMIC, 3" turbo back exhaust, VPC, GCC...... Now
>having said this the Galant runs 18-19psi on pump gas and
>really pulls, but there is no real kick until 14psi after
>that your thrown back in the seat. Bottom line is the Talon
>feels stronger in the early stages of boost then the Galant
>of course, but from my point of view I don't see the T3/T4
>being much fun unless you can run high boost levels.

Well thats just 420A superiority (joke). Really though your talking about a car that only had 7.8 compression and designed to spool a 14B, not to mention the added task of a pushing power thru a 4wheel drivetrain. it probably had hard enough time mustering up enough exhaust energy to spin the 14B down low let alone a T3/T4. 4G63 people complain of the S16G having too much lag, naturally a T3/T4 isn't going to help any. Also a T3/T4 with what specs. A T3/T4 with a .48 AR and stage 2 wheel is gonna spool helluva lot faster than one with a .82AR and stage 3 wheel. If there's no kick until 14psi how is a smaller turbo going to fix that?. the question is where do you reach 14psi? If you reach 14psi at say 3500rpms a smaller turbo isn't going to make it feel any faster except from 0-3500rpms and at part throttle. If you reach high boost above where its useful to you thats poor turbo selection or a set up being used outside its intended use (I suppose if Lisa Kubo's turbo doesn't kick in until 5500rpms it doesn't matter. I suppose your priority for choosing a T3/T4 to begin with was drag racing, hence the race gas). A star turbo kicks in fully by 3500rpms on a 2GNT which is plenty useful and feelable in normal driving situations.

Dyno numbers, I have no doubt the
>T3/T4 will make more power the the S16G at the same boost
>levels but my seat of the pants dyno says the S16G will feel
>stronger at that boost level because you'll be waiting
>forever for the T3/T4 to spool.

Again when a Star kits boost gauge reads 5psi, a S16G thats reading 5psi isn't going to feel faster as long as they are reading the same thing. it(S16G) may feel slower due to smaller compressor wheel/flow and smaller turbine/backpressure (I doubt heat is an issue with either at this point). It (S16G) will feel faster below the threshold of full boost (because its producing more boost) which happens to be around 3500rpms for the star kit. and throttle response will be better because it will likely still spool with less exhaust energy at any rpm. I think the S16G probably feels faster when not going all out (cruising, high gear passing, part throttle toying with hondas). From 3500rpm on @ full boost I really doubt it feels faster. There really isn't any waiting in the way that it sounds. You wait for 3500rpm and Smack full boost is almost instant. You dont HAVE to drive below 3500rpm except to take off smoothly (in other words if you want it bad enough the power is there with a star kit, you just may have to work for it sometimes. you may need to downshift when you dont feel like it on occasion. so what you look a little silly cruising at 3800rpms waiting for that honda in your rear view to come up on you. at least you wont be disappointed when you nail it when he's about next to you going full steam and there's still something left to take him).

>the two cars you are talking about are totaly different
>engines. One is a 2 liter V4 and the other a 3 liter V6.
>But I agree with you somewhat. I think Jason made a good
>point about the heat that a turbo makes. I didnt think about
>the heat factor. The t3/t4 probably does make a significant
>lower amount of heat due to its larger size therefore
>producing more hp at the same boost pressure. So I guess
>your right Greg.
>
>I like posts like this :-). I find this very interesting.


Dave_FL: Could you please explain yourself?? I was talking about a 99 Eclipse GSX and a 95 GSX (Brent Rau's car) and they both have the same power plant (4G63). Also there's no such thing as a V4 and who has a 3L V-6? you kinda lost me there. ;-)

When I saw the t88 turbo I immedietly thought of a supra. WHOOPS. I wasnt paying attention. Maybe I was drinking at the time I posted that..LOL.....Damn man a t88 turbo on an eclipse is huge!!! And the 3liter v6 is what is in the supras and the v4 would mean a 4 cylinder. I just didnt feel like typing out "4 cylinder" so i just said v4.

Off topic....Are you going to be here on the 22nd of march for the spring break thing? I hope so it will be fun. And we can hit the drag strip a couple times too.

the 2jz-gte is an inline 6 cyl.

A.D.P.
bring it on............

umm..u have a i-4, not a v4. and like armond already stated, the supra motor is a i-6, not a v6.

What turbo would be better for an auto?

>What turbo would be better for an auto?


Read up above and make your own conlusion. Being an auto you might want to have a quicker spool because we have absolutely no power down low. So you might want to remember that.

>>What turbo would be better for an auto?
>
>
>Read up above and make your own conlusion. Being an auto you
>might want to have a quicker spool because we have
>absolutely no power down low. So you might want to remember
>that.

Well let me be blunt. The 16G

you guys are so smart.
Dave your killing me

first v4.. then a supra with a v6 come on now.. even my slow butt knows its a inline

So "basically" what you guys are saying is...


the s16g spools quicker, but the t3/t4 makes more power in the long run ?


Im just a tad bit lost in all this turbo talk...


And also, does the Star kit have as many stages as the HRC kit ?

I don't think its possible to make a logical decision since there's so few of us and the times are so inconsistent. With everything installed right the 16g should definetly spool up quicker. Ideally the t3/t4 will allow for more power at the same boost level, but we aren't sure that the particular one that comes with all these kits is the optimal one for max power since there's so many different t3/t4 turbos out there. Another thing is piping and intercooler, i know hrc has the better intercooler, not sure which one has better piping.
This again brings up the advantage of hrc's research and racing background with the car, you can be pretty sure that what they provide is a good choice for our car. We don't know much about Star (except they made by Drag :) )

I was just trying to state that they they are 6 cylinder engines and we have 4 cylinder engines. Jeeeez, You guys are picky. You know what I ment. And yes, I know the supras are inline, but who really cares?

The Supra boys prolly do :) I also caught the V4 right off the back. We're a picky bunch. Eccentric really. No, really.