Hawthorne

Hi great site! I found it a few weeks ago and wish I had known about it 8 yrs ago when I got my CTD. Thanks to all those responsible for the tech info and the stickies. It really improved the power !!
I'm going to put in a 4" exhaust soon and wonder what other changes (turbo, 3200 spring) else anyone would suggest ? This truck is my daily driver and I tow a horse trailer a lot through the mountains.

wannadiesel

Definitely do the 3200 RPM spring. If you are having EGT problems (I imagine you are) the compressor upgrade would be a good next step.

90firstgen

With everything you have so far, the next things I would do are a 3200 spring and an HTT compressor upgrade (htturbo.com) Definately go for the Stage 4

91.5CTDBanks

Welcome. Have you done any air intake mods?

Hawthorne

Thanks for the suggestions. My EGT's get to 850*post turbo pretty quick climbing hills empty and they get hotter than that with the trailer. Can I keep the 18cm turbine with the HTT stage 3 or 4? Or do I have to change it to a 16cm with wastegate to bring my temps down? What boost levels are safe with these non i/c engines? I'm maxing out at 28psi now. I looked thru the archives on HTT stage 3&4 and found some good info but couldn't find out if I can keep my exhaust brake. Sorry about all the questions, any help from someone that has done this already would be great!

wannadiesel

If you are happy with the spoolup of the 18 cm, there's no reason to get rid of it.

You would only lose the exhaust brake if you went to a completely different turbo like an HTB2 or an HX-40.

Over 40 psi you are playing with a rattlesnake. The head gasket blowing becomes a question of "when?", not "if?"

Cowboy_Customs

Welcome to the site, n make yerself at home!
You are deffinatly on the right track, run your star wheel all the way down, and dump that K&N for the BHAF, I have heard bad things about K&N's n diesels.
The 3200 spring is amazing! I couldnt believe the difference when mine got put in.
The HTT stage IV is the route im going with anyway, n I do some hauling often.
I would opt for a different exhaust side too, a lot of guys run a 12CM, some with a 14CM. A waste gate is a good idea cause like dave said, its a matter of when, not if u blow that head gasket.
Im not the most Turbo knowledgeable person here, but I believe you will want to swap that exhaust side with a wastegate before the compressor side do to the fact the compressor ups the boost, n Ive seen 40PSI w/o one
Or headstuds n o-ringing n dont worry bout a wastegate!
Water/Meth for your Non-IC would be a huge help in power, and keeping your EGT's in check. Or do like G1625S n install a 3rd gen IC.
OH, n welcome to the "slippery slope of POWER!" please dont try to keep your grin hidden while smashing throttle after new modifications, and have a safe ride!

How do u like those BD injectors?? Its about time for more fuel for me.

dpuckett

I think an intercooler would be better than a water/meth system. But then I have no experience with the meth, just like to keep it simple.

On a 90, you have a 50mm impellar housing. Anything would be an upgrade, but you may have to get creative with the plumbing to get it to work, as the outlets are different from IC to nonIC.

Your (original) stock head gasket is good for like 30-35psi. They got bettter in 91 with the intercooling and marine grade HG. Your stock turbo loses efficiency at the mid 20s boost.

And move that pyrometer to the manifold. I know, your e-brake has a hole for it, but put a plug in there. I have seen 500+ deg differences from post to pre turbo, no other changes. If you were stock (and planned to stay that way), you might be ok, but since you are upgraded, and plan on more, keep it where it will do you some good. If you hit 1500deg, you may not know it til it's too late. And, likewise, if you keep it at 900deg, you may be able to push it more.

Basically, get some more air, cool it down, and enjoy.

Daniel

wannadiesel

Water/meth can create very high boost on non-wastegated systems.

G1625S

I've found a non-gated housing with stock non-ic injectors to be worthless once the pump is maxed. Move your pyro probe, tweek your pump and get an intercooler.

Hawthorne

Thanks for the input!! I'll move the pyro and try a BHAF, I talked to HTT and the stage 3 & 4 are out of stock for 4 weeks which will give me time to save up. If I put in an intercooler does the stock rad have to be changed to make room? My stock one is starting to show its age and if I replace it should it be a 91.5-93 type rad in case I put in a intercooler later ?