I went to a local diesel/turbo shop and purchased a Garrett GT-42. I am building a 408 cu.in iron block LS1 engine with AFR 225cc heads.

The turbo cartridge is the GT-42 (non ball bearing) 102mm wheel, 53 trim .60 A/R

The exhaust housing isn't the std T6, but it is a new Garrett T4 housing with a 1.01 A/R

The turbo seems rather large on the compressor side?? but the garrett catalog says it should work for my cubic inches and horsepower I wanna run

Did I make a mistake buying this, is here a better maybe smaller packaged turbo for my application??

 

I thought the 102mm was the turbine side. I think the 42 comes in 7x-mm or 82?mm compressor wheels sizes.

But I'm just going off the top of my head. Search or call Jose at forcedinductions.com.

 

No in the catalog is says either 94 or 102mm compressor wheels

 

Those would be the exducer sizes that the catalog lists. What you have is a 74mm compressor wheel at the inducer (in this picture the Dp). You should be ok, what power are you looking to run.




From what I'm FINALLY starting to learn...the "42" in the GT refers to the size of the turbine wheel, or in this instance 42mm.

 

Looking to make 750-800 rwhp. Is the PTE76GTS that everyone talks about bigger or smaller than what I have now, and does it make more horsepower. Also what are the GT42 turbos on www.forcedinductions.com:

GT-42 70T 950 1.15
GT-42 74T 1100 1.15
GT-42 76T 1200 1.15

 

Well...now that I reread your post...you could possibly have a 70 trim ( thought you said you had the 102) The PTE is a precission 76 mm inducer (I believe) without looking @ the compressor maps on them, I don't know what to tell you. Hopefully Jose or someone will see this and give you a more concrete answer...I'm getting better @ this...still a ways to go though.

 

102mm exducer means 74mm inducer. The turbo will make plenty of power up to a certain point. With the larger cubes your PR's aren't very high so you will be down somewhat on the efficiency of the turbo. The best units for a 408 and keeping a T4 will be the GT42-76, 76GTS (same thing as GT42-76) and PTE-88.

Jose

 

Oh and the 76GTS is larger then your current turbo.

Jose

 

Hey speaking of turbo sizes, you mentioned cubes and turbo efficency, what may I ask in general terms would you think would be the best setup for a 427 ci engine? I'm wondering because this is my plans, and money keeps building, so I'll be there at some point. Any suggestions?

I don't mean to hijack this thread at all, just wondering.

 

All depends on the level of horsepower you are looking for.

Jose

 

Okay so what is the GT42-76?? or the 76GTS do you have pictures of them, and what is the turbo I have now GT42-??, are these off the shelf Garrett parts that I can trade mine for or are these custom units. I think this GT42 I just got is pretty large, the exhaust side isn't big, but the compressor side is HUGH, how much larger is the GT42-76, 76GTS??

 

The unit you have now is the GT42-74T. The GT42-76T will look identical, just larger compressor wheel is stuffed in. The 76GTS is much smaller physically, but makes the same power.



The 76GTS is on the right.

Jose

 

well I am looking for something of smaller size, for packaging, could you please PM me a price on the 76GTS, and how long it will take to get?? Also what choice of A/Rs are there?

 

Well you want to run a .96A/R, thats the largest offered. I will pm you a price and I believe I have a unit in stock....


Jose

 

I knew Jose would know. Is my aprenticship growing Jose? I think some of your knowledge is starting to finally rub off.

 

Hehe, yes my young apprentice. Jose1 has taught you well

Jose

 

Hah, Turbo-wan Kenobi!

Just curious, but would a SBC be able to turn a pair of GTSs? I know they're some huge bastards, but I see 331 & 306ci Mustang guys turning some big *** singles.

 

You could turn them yes, as for peak torque (peak boost), well, around 7000rpms or so....lol. But then again most of the race cars run solid rollers and rev to the moon.

Jose

 

I figured I'd have to spin it like a rotary. I've been tossing ideas around for the next motor. Given the going rate on those babies, maybe I'll keep tossing.

 

No fair, you stoll my idea You thought about stepping down and running two 61s, 63s or 66s.? Where would they start to make max TQ Jose? Down the rev range judging by size, though if you wanted to do it on pump gas