Looking for compound kit & turbo size

[dirty_maxxbob]

Looking for a compound kit for strictly towing. I have a stealth 64 & 67, and I have a full WCFAB kit ie y-bridge hot & cold side pipes & intake. I was trying to find a WCFAB kit since I already have most of the parts and track bars. What would be the best S400 charger or GT charger for towing a 32’ 5th wheel around 19k have a built motor & trans SAC 45% over injectors and LBZ CP3 truck is CCLB 2WD


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[MarkBroviak]

An S476 would be the smallest I would use and a Billet S480 would be ideal for it! I prefer the way a larger atmosphere turbo act compared to a smaller one as they tend to be more two stroke like with bottom end lag then bam it hits hard then runs out up top faster. A larger turbo doesn't have that same lag on the bottom and pulls much smoother through the range and will have more topend power available. This will also all depend on how it is tuned also.

 

[dirty_maxxbob]

An S476 would be the smallest I would use and a Billet S480 would be ideal for it! I prefer the way a larger atmosphere turbo act compared to a smaller one as they tend to be more two stroke like with bottom end lag then bam it hits hard then runs out up top faster. A larger turbo doesn't have that same lag on the bottom and pulls much smoother through the range and will have more topend power available. This will also all depend on how it is tuned also.

What size exhaust housing would you go with on that s480? .96AR?


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[MarkBroviak]

1.32A/R T6 is the only way to go!

 

[MAXX IT OUT]

1.32A/R T6 is the only way to go!

I swapped to a 1.15AR on mine and it definently helps bring things on a bit quicker, but it all depends what RPM range you want to tow or race in. Since you have built engine and are looking at smaller turbos, your will probably tow completely different from mine. The other weekend i made a trip with a enclosed trailer to pick up a car in Chicago, then up to Wisconsin to get a piece of equipment, ending up at about 16000 gross. For my truck on the pretty hilly parts it liked about 60MPH in 4th TQ locked, run about 850 for EGT and about 78MPH in 5th TQ locked, running about 1050 for EGT.

 

[MarkBroviak]

Correct, but you are forcing it to come on sooner and for that you give up rpm range and you will pick up egt's because of it, but it matters where you operate it at and what you want from it.

 

[Chevy1925]

I liked the 1.15 on the 83mm but that turbo was race cover and billet wheel which moved far more air than the box stock 80mm I had before.

Personally, I didn’t notice much difference between a box stock 75mm and 80mm in the spool up department. The top end of the 80 was better. 83mm was when you really noticed what Mark is talking about but I think Anthony played with the gate more now on the stock turbo than I did and really made it work better (vane changes in your case)

The exhaust housing size won’t make or break the truck. Adding the second turbo will make a big difference either route you go. The housings and turbo size are a good way to fine tune in where you want to be though. It’s not as critical like a big single.

I’d start with the 80 and you decide on where you want the power coming in. Keep your tuning smart like Shane says as well. Kinda defeats the purpose of twins but it’s better than stock single turbo.

 

[MAXX IT OUT]

Correct, but you are forcing it to come on sooner and for that you give up rpm range and you will pick up egt's because of it, but it matters where you operate it at and what you want from it.

Agreed, if your under 4000RPM max and mainly towing, I don't think you will benefit from the 1.32. I will try to find my logs on the change between the 1.15 and 1.32. At more RPM than that, the factory turbo or S300 turbine wheel will be more of a restriction point than the Atmospheric turbo .