I was reading the post about belt driving a turbo and make it a supercharger.

I know nothing about turbo and supercharger, I'm just good building weird things

I can get this 3.8 turbo for 50$, it's new . is the "intake port ??" be large enough to supply a 305, 350 ? Since the "exaust port ??" would be removed and replaced by a set of pullies.

 

well, i believe it depends on how fast you are going to spin your impeller. you're going to have make some kind of multiplier to get high enough RPM's. an ATI Procharger spins around 45000, do your serpentine belts? just my thoughts...

 

Turbo impeller speed generally tops out around the 100K RPM point. I've seen much bigger speed than that, but that's what you should shoot for. I'm going to go on the record and say that I think this is a bad idea. I don't think the turbo bearing is going to like all of the belt tension force on it. Plus I don't know how the shaft would react. It could crack real easy. On the other side, if it works that's great.

 

Even if it could be done and work anywhere near well.....it would be easier to just make a single turbo setup.

 

ATOmonkey ... tought about the bearing and my idea was to mount another bearing on the exaust shaft to reduce the stress and build a bullet proof enclosure around the two pullies.


100 000 rpms ? that's alot ! hmmm.....not sure I can find pullies to match up these number I might be able to acheive 50 000-60 000 rpm but that would be the max . * I think*

Since it wouldn't be under extreme temperature I'm guessing it would be easier to find good bearings that support this kind of spinning. i have a book with over 3 millions of pullies, bearings and belts ...maybe it has something to offer ...

 

Seems like more of a hassle then it needs to be. If you want to do something similar think about something like we did on the 302 in my brother's LTD.

We got an Eaton M90 supercharger (the one that we used was off a 3.8L ford T-bird Super coupe, but the 3.8L GM engines use the same one with different pulley/drive/bypass... arrangements) for $150 with all the plumbing and IC, sold off the plumbing and IC for $150 , then we made brackets and intake ducting to use it with the 302. He’s run low 11’s at 119 so far, and since we found 2 more pounds boost and lightened the big 4 door some is hoping to see 10’s on radials this Friday. The advantage with the eaton over the turbo compressor is that it makes boost at low rpm’s also and doesn’t need nearly the rpm to work (I think it’s spinning in the 16-18K rpm range at the shift point right now).

 

yeah, i'm with crossfire. i think there are a lot easier ways to go about this. but if you're doing it just to see if you can, let us know what happens.

 

Is a diesel Turbo any different then a normal turbo ? I'm thinking it may requires less spin to produce a decent boost.

 

All turbos are created equal. Smaller turbos make boost faster, but all of them like to run around 100K RPM. Diesel Turbos generally have a larger compressor because they run around or over 20 psi on over 7 liters for a small engine.

 

ATOMonkey, you’ve got half of it right and half of it backwards.

A turbo is a turbo, there is nothing the distinguishes most diesel turbos from most others. The reason that I say most is that there are some gas turbos designed for blowthrew operation that have an extra seal on the compressor side. The T04’s that are the big upgrade turbos (and most of what turbonetics sells) are sizes/trims that used to be used on John Deere diesel tractors.

The part that you got backwards is the size. Most turbo’s that you’ll find on diesel’s are surprisingly small. The explanation is simple, it’s all about airflow, cfm = displacement*(rmp/2)*Ve(volumetric efficiency). So, yes, there are some big diesels out there, but that 7L will only see 3000rmp tops, so it only has a turbo comparable to one on a gas engine half it’s size.

 

BTW, diesels can run nut’s boost (100psi+), detonation isn’t an issue since that’s what makes them run, but very few do. Most are in the mid to low teens…

 

HHHHHMMMMMMMM......................

 

You're kidding, right? hehe.....um......right?

 

where do ou find a gauge that goes high?

 

Nope, dead serious. Like I said, they don't have to worry about detonation like us with gas engines, so their big concern is how much can they can stuff in before I break something.

Check out some of the tractor pullers... truely impressive, they're running 2 stage turbo setups topping out in the low 100's, and people are starting to tinker with 3 stage setups, the problem is that there aren't many turbos big enough to be the first one in that line, so they end up running 4 turbos...

The big problem is the heat production. The outlet temp on a turbo producing 15psi in it's efficientcy range is roughly 350*, so you can imagine what would happen if you're getting 3 or more times that and then 3 stages of that. Most run multiple stages of intercooling/water injection.

The other thing to consider is that in their case, it's not the ammount of air you can force in the combustion chamber, but the ammount of fuel. That's why things like straight propane injection are a 'power adder' in the deiesel world. For them, more fuel = more power and if you don't get enough air in there you end up melting parts...

 

okay, so if i take my chevy, 3500 flatbed, with the 6.5 turbo diesel, and want to crank up the boost, how would i do that? it's at like 17 #'s, what if if i want 25? can i do that? this is getting interesting...

ohh! i forgot. i can get my hands on an extra intercooler (ATI style) for dirt cheap. would it be worth it to slap that on this thing?

 

The intercooler would help some.

the truck... well, the basics are that you'd have to make a boost controller to fit in the pressure line to the wastegate. Essentially a valve and a blead. Do a search online and you'll find some premade ones and directions on how to make your own.

WRT that specific engine... Well, it's not the best thing that GM ever built (not the worst by a long shot). There is a pretty good chance that you will not be able to get much more boost into it. Depending on the year, they used one of 3 different IHI turbos that are really small. That makes them spool up faster and makes things more responsive at the lower rpm's that the truck spends most of it's time at but will restrict how much air you can pump. In an extreme case (I doubt that things are that close) the intercooler may even hurt if th pressure drop across it is greater then the ammount more that the turbo can pump. No matter what if you do that I'd consider moving the pressure pick up for the waste gate to after the IC (it's probably plumbed into the outlet of the turbo now).

I'd say it's worth a shot, but hell, I tinker with everything, even my K1500 truck and the wife's sunfire have made it to the track, and I managed to sneak a few tweaks (even a cold air intake...) on the wife's car...