The GT45 has the medium size turbine wheel(around 87mm). I've tried the 87mm turbine BW with 75, 78, and 80mm compressor wheels. It spools a bunch slower than the 83mm turbine(couldn't tell much difference between the 87 and the 96). I have heard that the GT45 is the same way. Spools more like a GT47 than a GT42. There are still turbo shops that don't recommend the BB chargers in diesel applications. I'm sure there will be opinions to the contrary, but I heard it again this morning. There is also alot of talk about the Gt42 with the 80mm compressor. I asked about one of those last week at a shop that is often mentioned here(in a good way), he was hesitant. Concern for the small turbine on the 42 was the issue. If any shop would like to chime in here, i'd love to hear your opinion. I've bought and tried 25-30 chargers so far. Not afraid to try another, but I won't pull punches about the results.(unless I start getting a discount ).

 

Ron what unit would you suggest then? I am about to upgrade my setup to the replacement of the S480 which is the new Billet ETT 82mm from the guys in my sig, which might be the same company your talking to?. Do you think that will support another 80-100hp and still spool the same?? Have you tried that charger?

 

When you ask me a turbo question, keep in mind that if I knew what i am doing I would only have bought 2 chargers. I'm running a 64/71/16 over S480w/race cover. I have not gained anything on the dyno over the 75/83/1.1 S400 I had before this. It feels stronger on top, but lost on the bottom and mid range. I don't plan on trying any more S400 chargers. Jose told me about the billet wheel, but I would rather look for something with a slightly smaller turbine and housing. I have a GT80 w/1.08 on order. Not sure where you are power wise. I made 711 with the 75/83/1.1 and 694 with the S480. I think it's just a matter of too much fuel on the bottom, but I haven't had a chance to sort it out.

 

NOW we have real world hands on info .I have a s480 with the race cover on 1.32 ar really thinking about going to a 1.10 ar with 83 or 87 wheel . also had a s475 1.32 ar worked nice in my setup . I will say when i ran a 64 65 14 top it was solw to boost up now with a 62 65 ss13 very nice to drive

 

Diesel-Dummy.
You may find these two dyno sheets interesting. Same dyno, different days. First is an S400(75/83/1.1) Mach 6's with 181 dv's.(a very nice spooling daily driver setup).

 

This run is with the same secondary, an S480(80/96/1.32/ race cover). Mach 7's, 022 dv's and 120 dv holders(too much fuel on the bottom).17hp less(huge difference in how they drive)

 

Thanks for the info did you ever go back to the fuel setup you had on in the first dyno but just change to the s-480 ??

 

That's the plan next time i get a chance. I like the 480. It daily drives fine, but coupled with the 64/71/16, it is a bit lazy. Don't make fun of the guys that are big into theory. I've seen several nail twins on their first try with some odd setups. Makes me jealous as heck.

 

If you're starting to cleaning up the smoke at wot, go with more fuel, forget the turbo upgrade. If you're black thick smoke, you need more air, buy a bigger turbo. IMO, the best way for big turbo to spool decently in a big HP daily street driven truck, is with a ball bearing unit. Yes, are expensive, but you get what you pay for. If you're just into making big numbers, go with the NOS, its easier and twins isn't as important.

Just had plug for ball bearing turbo's, my garrett 3782R is still spooling nice.