This truck is about to become a second driver and strictly a play toy..SOO I am going to put twins on it. With that being said what would be the best turbo to setup with my current HTT for best spoolup. I am not worried about cooling as I do not tow and I want to have an efficient 500-550 hp. Also how many are running twins without studs or o-rings as I am not really looking at dropping 2K+ on headwork just yet. I know I will be on borrowed time, but I'm use to it with my VP . Can I just wastegate them down to 45-50 or what? Any suggestions would be helpful. What would be even more helpful if there was an ideal turbo to match with mine that is run on either a Caterpillar motor or any medium to big-rig trucks as I have access to Holt Caterpillar and an 18-wheeler truck yard..

 

i'd say an s400 for bottom turbo... but going twins with a htt up top is gonna put u over 550hp very easily.... i'd say 650-700hp ....

 

hmm which is gonna require bigger injectors, and head work...and a new clutch

 

any other options

 

a b2, s400/b2 or a s400...

 

k31 is the way to go wastegated so you can set it to stay under 50 psi until you get studs and head work. you can get them off ebay and you can switch it out with a s400,they are interchangable.

 

so a K31 on the bottom of my HTT. How much and who makes the K31?

 

its a s400 upgrade turbo and pm me for maore info maybe a couple of links if i can find them.

 

To get that HO above 550 without any drugs you are going to have to do something with that VP and bigger injectors . You can make it for awhile without studs. But you will need them and head work. Post the results if you do it because I plan on doing the same thing. Good luck.

 

Get some mach 5.7's then a set of studs next

 

for that power level, just use a k31 on bottom

 

thanks for the info guys...gonna check into this K31 everyone has mentioned...From what I have heard though the s400 on bottom would be the ideal setup so if I were to go that route it looks like lots of upgrades are in store...

 

The K31 is made by KKK a division of Borg Warner. The wastegated version isn't totally interchangable. It is longer than the S400 due to the wastegate. The K31 flows about 90lbs/min vs. 96lbs/min on the S400. The S400 has a slightly bigger exhaust housing and a much bigger exhaust wheel so it does spool a bit slower. In general the S400 is a much stronger turbo. It has a considerably bigger turbine shaft. Be careful with the K31 as they have been known to have the thrust bearings beat out of them with high hp in stock form.

 

thanks for the info man..

 

ive had the k31 on my truck for a little over a year and have had no problem i do use it for daily driving. and have had it recently worked on and had some enlarging done to the front compressor sizing.it now flows a little more than a s400 and had some bearing work done along with some maching and rear turbine and blade work. i like much more than the s400 daily driving with a large top turbo. the s400 i use for dyno and drag etc.... its also not a standard s400. i would say get the k31 its a string turbo and will fit you well, and you can tow really nicely and once you have head work you can turn it up. i used a 6psi wastegate off of a small schwitzer turbo and it went right in and a piece of all thread and wham everything works great then a boost elbow so i can adjust everything.