Spooler

The GTX4508 is an expensive turbo. This setup was the most expensive. Around 7500 with an HTT manifold (Steedspeed would be more), hence the reason I am waiting....LOL

soulezoo

I was referring to the regular gt4508r and not the gtx. It isn't necessary for 700hp.

soulezoo

From a drive pressure point of view, absolutely the 3788/4508 is superior. Larger turbines, larger EH's. This setup will spool nearly the same if not slightly sooner (but more linear) than your stock HE351 on stock tuning.

Also, the 3582/4202 will not support the power your injectors have to potential to put out. Of course, you can always tune it back to the turbos with the efi live.

One big and very noticeable difference, these turbos are loud! They will scream and roar like an airplane taking off when you get on it.

soulezoo

You already have a 3782r, right? The 3788 doesn't spool very different. A good cam should be on your to do list and that will help spool too.

commtrd

YES! Gotta have the Garrett scream! What would be the recommended cam for this application? Hamilton 188/220? Think I will get a Helmann CAC. Don't know whether to look into dual stock CP3s (what I would like to do) or if a stroker single would feed the rail OK?

THANKS for the advice! Agonized over this turbo selection thing for too long. For noobs trying to do it right can be really hard to get to the right place.

commtrd

I think using the 3782 I already have for the secondary makes good sense. Helps save some money to go towards that expensive 4508 and a cam and an intercooler and do something about the CP3. Well I need to get the head studs and springs going too. So yeah re-using my 3782 would be a good thing but would be nice if I could get the ratty looking turbine housing coated with silver ceramic or black anything but rust.

soulezoo

No, I don't think the Hamilton is the best for you honestly. That cam is more suited to those that want to play in the upper RPM range. You don't.

I would more likely recommend the Colt Stage 3 as I think (Just my honest opinion, nothing more- please no flaming) it has better low end to mid range performance curve over the Hamilton 188. The Hamilton would have better high range breathing performance at the expense of low end spool. The question to ask yourself is where is 95% of your need?

I know for a fact you don't need dual pumps and something the equivalent of a Floor It stage 3 would handle the injectors just fine. I have had one working flawlessly now for nearly 70k miles.

soulezoo

Talk to Tom about upgrading your present turbo. I am sure he can do something at a lot less $$ than a new one. Tell him I referred you.

Spooler

Soulezoo, Who's CAC are you running?

soulezoo

Htt....

Spooler

Hamilton makes a great product. The 188/208 is more suited to towards his needs. He also has the 178/208 which I have also ran and it has gobs of torque down low. More suited for 3.42 geared trucks or trucks with 3.73 and larger tires.

Spooler

How much bigger than stock is it? I have a fan in the front for my A/C. I need to keep the room...LOL Much more important for me to be cool.

soulezoo

Quite a bit bigger... a LOT heavier.

It hangs a lot lower than stock but I don't think it is all that much thicker. It may not interfere with the fan you speak of, but I would check to find out. I don't have specs at hand.

commtrd

Who sells the Floor-It CP3? Haven't heard of that one. I will check on that Colt cam as I am much more interested in low-end torque and fuel economy with great EGTs. Can probably tell I'm not a hot-rodder at all. Just these 3rd gen trucks have such classic lines (and of course the Cummins) I want to keep it forever and running awesome too. BY THE WAY 600 hp really is not a wimpy truck at all... Just thought I would throw that out there. Here is a great question: is it better to have spool on secondary right off idle OR lower drive pressure and good spool maybe couple hundred rpm higher and have a real torquey cam so that would be better for the engine? Or would a good size external gate around secondary be just as good far as drive pressure?

soulezoo

At your power level, you're thinking too hard about it. You really are not going to "need" the external gate. But it will improve drive pressure if you are over 3400 rpm or so. 600hp is never wimpy, you are correct. But folks with the power bug... well, you know.
As far as the great question, the correct answer is "it depends". Depends on what you want. Doesn't matter what I or anyone else wants. I will tell you that if you are happy with the way your turbo spools now, going with the aforementioned recommendations you won't be much different and maybe even slightly better.

The cam can be had through Peak Performance Diesel... google them and go to the website. Look for the "big stick" cam. It splits the difference between a "torque" cam and the Hamilton 188; in fact, the big stick provided the genesis for Hamilton's cams (but was developed by Colt). You will like it a lot.