Originally posted by Matt S
With this turbo, would you need a 4" downpipe or will a 3" work?
IMHO 4" is a good size for exhaust on the 5. 9CTD. I have heard of very little HP increases on Dyno's. There is no Doubt That it helps some with Spoolup, Lower Egt's, Deeper "BigRig" Sound. But having said all that - 4" is way down my list as "Gotta Have It's".
What horsepower levels is this for?
The KS12cm2 works well on a "Stage 1" level truck and above. That is anything above stock up to 450HP. Higher HP trucks still benefit from the KS Turbo but they can really use more air.
Is there a lag difference between the HX-35 vs the HX-40 with the 12 cm2 housing?
On my Moderately Fueled truck it is so close to stock spoolup I am not sure if one is different than the other. I would think it has to be 5% slower due to the higher weight of the Hx40 wheel. But as the boost comes in the power rush is greater due to the larger wheels.
I don't have an auto so I don't have a reference to your building boost at 1500 RPM. Is that where the HX-35 started to build boost?
That is where most of the Hx35's seem to come in but I have always run a PE Box and I think that is where they start coming on. And that will also Kick the Turbo into action.
I understand your comments of less boost with more power but how much boost will this handle. I've heard the HX-40 doesn't do well with a lot of boost.
I recommend that the (KS12cm2)Hx40 Turbos be set no higher than 36psi to a MAX of 40 psi. I believe Piers also recommends 36psi. The Hx40's will produce over 50psi but they are way past their design and it stresses the turbine wheel. I have yet to see a HX40 turbo fail that has not been pushed past 38psi atleast once. The one I have Blown up was pushed past 50psi for several weeks before failure. It failed at about 30psi but it failed due to overspeed. IMHO
How much of a reduction in EGT's can I expect?
It Varies from truck to truck. But all of my installations of KS turbos and stock Hx40's have reported a reduction in Egt's. If you stay with 3" exhaust you may only see 100 or 150 deg reduction. But along with a 4" exhaust and a better air induction like a
Genuine Physcotty air system you may see 300 deg drop.
What is the silencer ring and why would I need it?
The silencer ring is a metal ring plate that is OEM installed on the intake side of the turbo. It quiets the whine of the stock turbo. With the Hx40 or KS Turbos the whine is not a HIGH Pitched and generally not an issue.
I'm looking for more power with less EGT's but a 4" exhaust is a very tight fit with the transfer case in a 1st Gen.
It's tight on the new trucks also but a good exhaust guy has no problem dealing witjh it. My Exhaust guy Greg (Mighty Muffler) In Phoenix Az is a "Muffler God" he fit 5" from my Down pipe back!