Using the stock turbo & s400 or k-31 for twins

osci

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New to this site, and can't find the info that i'm looking for. Does anybody run the stock turbo with a 400 or k-31 on a 4.5 with auto. I'm looking at these steups along with a s300 (12) /400. My main concern is drive ability ( spool) in city traffic up to 40 mph. Next, is towing often either of my 12 k trailers. I don't want do any other upgrades other than whats in my sig, and hp being about 625, but not in the 700s. I have spoke with several vendors who sell each of these, but 1 only utilizes the stock turbo. I feel the stock turbo may run out of air quicky along with huge drive pressures. Scott
 
A 35/3b combo is a great around town towing set of twins. Check into relentless diesel's arctic air twins. They utilize the factory turbo and are pretty fairly priced. A 62/s400 combo would spool just a tick slower but will cool much better.
 
I am currently running an externally gated II PS62 over an S400 with a 74 mm wheel - B2 turbo. At the horsepower levels you are talking about they run great. I also have a Banks IC and Helix 2 cam.

With the fuel I have and all the other mods, I can actually build a small amount of boost in neutral. I think the cam has more to do with that than anything else honestly.

Not sure how it would do for towing. Think it would have a lot to do with the torque converter you are running in your DTT. I am running a tight one in mine, and am not set up for towing. I would call DTT to discuss with them, as they helped me a lot in my original choice with these turbos.

Chris at Relentless would be a good person to talk with as well.
 
MPI IS WHO YOU WANT TO TALK TO. nATHAN HAS A SET USING YOUR STOCKER OVER THE S-400. tHAT COMBO IS GOOD ENOUGH FOR AROURND 600-650ISH AND LOW 12'S IN THE QTR WITH SUPPORTING MODS. iT IS VERY STREETABLE AND TOWS UNLIKE ANY OTHER. INSTANT SPOOL UP
 
My coverter is tight and built for towing by Bill. With my 4.10a gears now, i have no lag even with the box off and just the injectors. At this point I can only use a small amont of additional power before i run out of air. I have talked with Nathan in detail for awhile about the stock turbo. If i was able to find someone running a similar set up, take it for a ride and hook up the trailer, I would know very quickly which of these sets would or wouldn't work.
Another friendr has a similar set up as mine with 3.73s a s300(14) / 400 which we will try in a few weeks.
 
I just installed a set of 62-14/GT42 MPI twins on my truck and they spool wicked fast. My concerns were the same as yours as I need my truck to pull a travel trailer and here in NJ we have alot of traffic lights and stop and go traffic. I've only had them on for two days but I can already see that they will spool great in a towing application.
With just the 62-14 I could bury the pyro and now I can't get over 1200* with the new twin setup.
 
Oh yeah, forgot to mention the towing. I pull up to 14k with these twins and they couldn't work any better.
 
You could use the stock turbo and if it seemed to run hot you could also just get a bigger exhaust housing put on it....would get more lag out of it, but it should spool real fast anyway, so it probably wouldn't be an issue.
 
What is included in the arctic kit? It seems this would be a fairly simple project to tackle on my own. Fab a spacer so the turbo will clear, fab up intake exhaust.... oil lines. Am i missing anything.
 
Joediesel, I've got to say that's the best looking d-max I've seen.

I was considering a 35/400 combo but was talked out of it so get a 62mm and then build the twins off of that. The 35 can only flow so much air.
 
thnx i wish it was my truck. id like around 600-700hp. i want to keep it cheap. so hx40 with s400?
 
If you can find a good used s300 turbo, I was told that the s300/s400 combo is very good.
 
Sorry for the highjack but,

I"ve got a II Silver 62 ordered with a 12cm exhst. housing....had a few pm's with Nathan......I'll still confused as to what my best choice will be for my bottom turbo.....S400, GT42, or spring for the S480????????
I'm wanting fast spool for daily driving.....Nat says I'll loose about 100-200 rpms of spool with the s400.........What would it be like with an S480???
He said my 12cm housing on the 62 might be a little small for the s480....

Looking for enough air to venture up to the 700 ish area....

Any thoughts??
 
I love my MPI set and Nathan is one hell of a good guy.. I know I am going bigger this summer but for now the stocker over the s400 is the ****... I tow 12-14k daily and even doing 80 up long grades I have NEVER seen a temp of 1500!! I can scorch the hell out of my 35" toyos and love every minute of it...:rockwoot:
 
Listen to Nathan, he knows what he is talking about!

Jim

OH! just to make myself clear, I was/am NEVER doubting Nathan.........I was just simply wanting other input before I charged the Big ONE on my card!!!

Thanks guys!!
 
I love my MPI set and Nathan is one hell of a good guy.. I know I am going bigger this summer but for now the stocker over the s400 is the ****... I tow 12-14k daily and even doing 80 up long grades I have NEVER seen a temp of 1500!! I can scorch the hell out of my 35" toyos and love every minute of it...:rockwoot:

Are there different messurements on the s400??? Or are they all the same??

So, If you Love the stocker with s400, My 62/12 should spool nice and give me a little extra huh???? Cause I need to tow some but not that heavy...Just a two horse trailer from time to time..( with a 2000 lbs Clydesdale on it though)........

Do you have dyno #'s on your setup?? (EDIT- Never mind, just saw your Sig. :doh:) How much psi are you making with that setup??
 
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