I have a '93 12V in an old Chevy pickup, I've already done a lot of the normal upgrades: 3200 gov spring, fuel pin, pump turned up (not all the way, but a couple turns), 4" exhaust, slightly bigger injectors from DDP (~50 hp is what they claimed), 94-02 intercooler. I have an M&H timing spacer to install very soon. Trans is a Getrag 5 speed.

The big detail is that I already have the 60mm upgrade for the stock 1st gen turbo, as the stock turbo setup barked quite bad after the fuel pin.

I have the opportunity to get an HE351CW from a friend for $200, he went to a bigger turbo.

I often drive this truck daily but it does see quite a bit of towing duty, though only 6-7K.

Honestly, I'm fairly happy with what I have, but if it could be a little better, I'd be all for it. IMO, the turbo spools a little slow now (still the stock housing, 18.5 cm^2 I think). Once the turbo is spooled, I have a light haze at full throttle at ~30 psi boost. I use the truck around 6000 ft and sometimes higher, so that works the turbo harder.

So, my take is that the 9cm^2 exhaust housing will spool quicker, right? Also, the exhaust housing is 4" rather than the smaller H1C housing, which seems like it can't do anything but help as well (since I already have 4" exhaust). I'm sure I can still get a bit more fuel by turning the pump up more.

Right now, even unloaded, I have to be pretty conservative with the throttle to keep it from smoking at lower RPM, if the mileage and drivability could be better I'd be all for it.

Thoughts would be much appreciated

 

you could just throw a 12cm exhaust on if your still running a big worthless 18.5 or 21. however $200 for a agood he-351 is a great buy,they work well. ive run both and tow alot in the mountains. the he-351 cools egts a little better but the hybrid has less drive pressure

 

I've certainly had that thought, but it seems like I could install the HE351 for nearly the cost of the exhaust housing, plus I could sell my current turbo.

The only downfall I can see, other than the work, is that EGT's may be higher with the smaller exhaust housing. Does that sound right?

 

One more point, I don't plan on any future mods.

 

do it, youll love it, down the road, youll be ready for more fuel, if you so desire.

 

x2 sooty. i love the mod, read post's on the mod before starting. i chose 12 o'clock on discharge. some use about 6 o'clock. if you go 6 you will have to fab a wg bracket. with the solenoid on the turbo the wg opening is set at 20 psi. you will need to add spring tension to it to bring the opening to 33 psi or change the wg to a adjustable one. it is very easy to adjust on the bench, use your paint spray regulator to get the 33 psi opening. the solenoid does nothing but must be there to keep some ports closed. fabricating the down pipe was hardest. took about 2 hours for me but someone use to working with exhaust could do it in 20 minutes.

 

I've spent hours researching

So advantages would be more air, faster spool time and a bigger exhaust outlet. Sound right?

What are the downfalls? My only guess is higher EGT's with the smaller exhaust housing. Right now I have very little issue with EGT's, the only time I break 1300 is towing 7K or so at 70 MPH in OD at a 6% grade for at least a half mile.

I see lots of reference to the wastegate and welding it shut, etc. Any reason I'd want a wastegate? I understand the purpose of it but I don't think I'm running (or would be running) enough boost to hurt anything.

 

Also, I assume that the smaller exhaust housing means higher drive pressure, which in this case is a bad thing. Right?

 

I say go for it I just got mine all buttoned up and love it. I left the housing clocked so the waste gate would be functional. I have it set to open at 38psi.

 

Smaller housing but larger outlet (4" VS 3") so it still rids the exhaust well. I think the "top end egt issue" is over inflated. Yes the drive pressures are higher than other larger housings.