Why no turbos using a GT28[RS] CHRA?

[HokieDSM]

I've been doing a lot of exploring around the Dual Ball-bearing turbos lately, and I'm looking for something along the lines of an AGP SS44, SBR GT10, or the defunct FP 2544. My question is - it seems all of these turbos use the Garrett GT25R CHRA, but given the information that I've read- it seems a GT28 would be better suited towards our engines, and provide a midground between the GT25 series and the GT30 series.

Does anyone know of a DSM turbo using the GT28 CHRA? It seems like the GT28RS is the "hot ticket" for a lot of turbo applications in our displacement area - but I've not heard of a DSM using one - though it'd seem to be a faster spooling and more powerful setup than the SS44/GT10/etc...

 

[asian312]

Mainly I think it has to do with bang for buck. The GT28RS in plain form are rated roughly for ~320. With a price tag over 1K plus the supporting mods such as manifold and o2 housing to make it fit, it becomes an expensive venture. In the DSM world your looking at the 14B, 16G, and Big 16G. Comparitivly the are respectably good for 250-350 HP with decent spool times and a price tag of free - $550 for a new Big 16G.

If your looking at component wise, the CHAR has less of a role in spool characteristics than the comp and turbine wheels. CHAR are generally chosen based on what size wheels and housings they can support. And longevity of the components, shafts, bearings, etc. And of course there's the price.

 

[kpt4321]

Good post by asian312.

The GT28RS is capable of almost exactly the same airflow as a big 16g; except, it costs 3 times as much for the turbo (~$1500). I can't justify that.

What kind of power do you want to make? One of your aforementioned 44 lb/min turbos might be just what you need.

 

[sweet97]

Kyle if I am reading you correctly the EVO is a 44lb/min turbo and the AGP RS49 I am getting is a 49lb/min. Please unconfuse me? i liked the EVO in 1st and 2nd gears and got into tuning quite well with the Scanmaster. I missed the pull my 20G equipped '89 Conquest had through all, even 5th gear. It spooled slowly (20G),15 psi by 3500 I believe-could have been 4K. 20 PSI @ 5k and 27+psi at 6k. 17mm internal wastgate. Kinda wonder why someone would do that. Now there is some concern for a 38mm which is 5 times the size of that 17mm. Well I should know by the end of the week. I just thought of a new post. Mark

 

[NDgsx]

The GT28RS won't bolt into the standard mitsu style turbine housings that are out.

As it was already stated the evo 3 16g is just as capable at an extremely low price. One of my customers put down 330ft lbs of torque on a dynapack, on pumpgas at 20psi. I don't remember the hp number.
Lightly modded car, ported 2G manifold, ported 1G o2 housing (don't ask), our 3" turboback, JR's ic, our piping, 2G mas, injen intake, rochester 550s, supra pump, sx fpr, and an afc.
He gets 20psi around 3300 and the response is great. I don't see the point in a GT turbo that size.

 

[HokieDSM]

He gets 20psi around 3300 and the response is great.

Now that is where I'm looking to be, if not better. The flow isn't so much as the boost threshold and transient response is what I've been looking for. I know the GT28RS won't bolt to the manifold - which is why I was asking why no one's used the CHRA only from that setup, considering that the 44lb/min setups are currently using the (not as good it seems) GT25R CHRA.

Assuming one was rebuilding an EvoIII 16g, could one replace the CHRA with the Garrett Ballistic unit?

 

[yo2001]

Assuming one was rebuilding an EvoIII 16g, could one replace the CHRA with the Garrett Ballistic unit?

I doubt it, the shaft size is complete different.

With my EBC and EVOIII, there is almost no threshold.

 

[BertMcGertPI]

just as a thought if your interested here is a link with a full garret turbo system with everything needed for installation http://www.turbokits.com/eclipse_turbo_kits.html

 

[BertMcGertPI]

although the price range is a bit high

 

[djsven]

Those prices are high. go to agp and you get a ball bearing turbo kit for $2200!!
And the only kit we can use is the one that uses a garret T25. Isn't that simular to what we have stock?

 

[prostreetdsmx1]

The GT28RS is really a nice turbo but i dont think it provides the power that the DSM community is looking for. with a retail price tag of close to 1500 you will be quite limited to under 350hp. We have used this turbo on various SR20DET motors and it is a strong turbo, with descent spool but i think that a DSMer would get boared with it.

if you look at the numbers on Garretts Catalog you will see it is rated to flow under 40lbs/min.
http://www.thespeedfactor.com/files/1/gt28rs.jpg

 

[jake98gst]

The reason you've heard of the GT28RS is because SCC. Putting it on their Project Silvia and naming it the Disco Potato made is "supa fly." THey justified it by claiming good spool. Whatever. However, SCC did run consistent mid-12s in it, I think.

Jake

 

[midnght]

The reason you've heard of the GT28RS is because SCC. Putting it on their Project Silvia and naming it the Disco Potato made is "supa fly." THey justified it by claiming good spool. Whatever. However, SCC did run consistent mid-12s in it, I think.

Jake

For the power and hit it makes seems a little high for a RWD boosted magazine car.

 

[EvoGun]

Disco Patato is not my first choice. I would be looking at the GT2871R. But that's me. Its good for over 400hp and spools just as fast. I think would make a great road corse car.

Thanks

 

[nicknorth11]

this turbo spools faster than any of my friends turbos on their dsm's....it is insane how fast it spools. the downfall is the price, but if you can afford it, it's worth it. i haven't been to the track yet, but without having all that many mods done, i can gaurantee i will be in the 13's and with some more mods this summer, the high 12's. you will be VERY happy with this turbo. and you will NOT get bored of it. my car is faster than just about every other dsm in my area!

 

[prostreetdsmx1]

the 2871 is showing to be quite a nice turbo, we have seen it run consistant 350whp with great throttle response. we have mainly used these on SR20DETs and MR-2's and man it's fun to dirve.

 

[EvoGun]

nicknorth11

What RPM do you see full boost in 3rd gear, also what housing is yours? Did you go 64. or 82.

Thanks

 

[LandoAWD]

i can gaurantee i will be in the 13's and with some more mods this summer, the high 12's.

Was it worth the money to be at 14b powered times? Not bashing, just curious as to the train of thought here.

 

[nicknorth11]

to be honest, i have only driven the car about 45 minutes with the new turbo on cuz i'm havin the engine stroked to a 2.3 with eagle rods and weisco pistons. the spool up is rediculous. it starts around 2700 rpm...im not too sure where full boost is, but i'll have my car back in less than a month so i'll be able to tell you then. im not too sure about the housing, i don't think it's the 82, but i'll try to find out.

when i bought the turbo i didn't plan on going above 350hp, that's why i chose the gt28rs in the first place, i wanted to get that power as fast as i could. honestly, i think i'll be able to get my car into the low 12's by this summer, i just didn't want anyone bashin me if they didn't think it was possible. i am absolutely happy that i did buy it though, it will kill most 14b's....and 16g's. some of my friends have 16g's, and t3/t4's, i beat all of them, just because their turbo's spool up so much slower. and im not saying they spool up slow, it's just that if you haven't seen how fast these ball bearing turbos spool up, ur missin out.

 

[Mackzero]

I know of a couple guys running the "disco potato" on their 1.8L VW GTIs. They spool very well and pull hard up top. I will comment on one thing though. Just because you spool faster does not mean you can pull on cars that have T3/T4 setups. I have a lot of buddies that have quick spooling turbo cars, and I can walk on them all day. I spool my GT3255 at around 3300-3400 rpms (23 psi) and once it spools, lag doesn't matter any more. I would think that the GT28RS would be great for auto-x and road race though. Where throttle response and lag are very important. And I bet your car will be fun to drive with the stroker and quick boost response. As long as you like it, that is what matters.

 

[pboglio]

Why does no one run the GT28RS CHRA? Because there is minimal advantage on a turbo this small and the price is higher. The FPBig28 uses the same 62 trim compressor and 76 trim turbine wheels but a standard thrust bearing. You can't spool a turbo faster than the compressor will allow, not going to happen due to surge. This leaves only boost recovery when lifting at higher rpms as a possible advantage. Anybody that has driven a car with this compressor wheel on it can tell you boost recovery between shifts happens before your foot even hits half throttle. I would not waste my money on a BB CHRA for a turbo this small unless I had an Auto-x car and had sponsorship.

 

[Jazzie6044]

Hey nick, I see youre just a couple of minutes away. Id like to see you setup sometime.

 

[nicknorth11]

my car is all torn apart right now, but i'll have it back in about a month, anyway, my email is [email protected] if you wanna talk sometime.

 

[nicknorth11]

p.s.~ if you read the prior post you will see that i didn't plan on going over 350 when i bought the turbo, SO DON'T HATE, FOCKERS!