SMOKEDOG

can anyone point me in the right direction so i can build my own 5 inch down pipe off an ht3b. where can i find material and a v-band. thanks alot

KATOOM

First off I hope you dont expect your HX35 to last while pushing boost that high. As for the 5 in. exhaust, I dont know what kinda power you have but if its not up there around 400+ then you'll be decreasing power and torque by having exhaust that big.

kyle@ftlb

first off his HX35 is fine... Looks like your in colorado, i think you have six states distributers out there, they sell a piece to fit the v-band over and then you build your downpipe onto that. Bring your turbo there because its is a really really tight fit, so try a few on it to get the one taht fits the best. Some people build there pipe with 2 60 degree bends and some use 45 degree. Most shops that supply parts for semi trucks will stock it or they probably can order it in. I know six states has the stuff you need though.

1320

I just got done with mine....like an hour ago was the test drive.

I bought a 5 inch down pipe from a volvo truck dealer then cut it up. The down pipe and v band clamp wa about 100$.

I had to cut a notch in the down pipe as it goes past the bell housing bolts. It would have fit, but would probbaly rattle or vibrate. So I cut a contoured notch out then filled the sides in. Came out pretty decent.

I reduce to my original 4 inch exhuast at the cross member, just before it goes into my us gear decelerator.

BTW, I ll be in colorado next week, near peublo.

msing

Phone around to big rig dealers,part suppliers look in yellow pages I found a big difference in pricing from one to another.

bmoeller

Not necessarily. Had a 5" exhaust before any fuel mods. Never felt a loss at all in power. It improved my bottom end power and the turbo spooled-up faster.

rattle_rattle

What's wrong with 38 PSI boost with the HX-35?

KATOOM

Cant really believe no one else here has said this to you before but your falling out of the efficientcy map of the HX35. Your probably creating more heat than your doing good. And spinning a turbo faster than it supposed to could (I'm saying could) cause mechanical failure. I suppose a quick burst to 38 psi isnt as bad as flying around those Colorado mountains at a constant 38 psi. And I realize that there's probably others pushing the envelope even higher but realize something, a stock engine makes the HX35 spin a 150,000 rpm! Thats only around 19 psi!

1320, Its great you have a 5" but really if your going for 5" flow you are only going to only get 4". Since you tied into your existing 4". Probably sounds good though.

bmoeller, maybe your didnt FEEL your loss but I wouldnt say that all those reputable shops that sell exhaust systems, install high perfomance parts, use dyno's, and not to mention give major advise on this site are wrong! It's proven that exhaust that is to big for your HP output will decrease performance. One exhaust company even found that using a 3.5" down pipe to a 4" system works better for motors close to stock. But hey, I'm just relaying info here.

SMOKEDOG, have you talked to any guys selling exhaust? What do they say?

1320

Not really.....the exit at my ht3b is 5 inch, as gases exit the turbo they expand and cool. As gases cool, they get more dense and require less space for the same flow. In the real world you could reduce the size even further and not hurt performance at all. The large sizes out back....don t do anything.

Mine is 5 inch to the cross member, plus I have a us gear decelerator, that is 4 inch...mounted behind the crossmeber, they are kinda pricey so replacing it wasn t an option.

bmoeller

Never said they were all wrong. If I am, it wasn't enough to notice. It would also depend on the condition of the old system that is being replaced.

Have had a cat plug on a car before. I can't say it didn't cause a problem. Took a long time to show up. Same thing happened to my boss on his '97 GMC. Wound up blowing the headgasket.

I'm just saying, if it can breath better by reducing pumping losses, it can be benfical. It was in my case.

KATOOM

Yes your right, as the gases cool they do in fact become less dense. But non the less you can only expect your exhaust to flow as much as the largest opening of your system, which is 4".


bmoeller, yes opening up the exhaust is beneficial but again, the main reason you dont want a HUGE exhaust system on a lower HP ride is because those gases that cool to quickly (because of you motors lacking ability to create enough heat to support that much pipe volume) are now to slow for the oncoming gases. Thus creating mass turbulance. This lowers go fast numbers!
Hey I'm not saying your truck doesnt feel great. Probably a heck of a lot faster than mine but I'm not here to debate you, just give SMOKEDOG some usable info.