"No buck" turbo UPDATE

[exwestracer]

I had posted in the turbo "say hi" thread, but figured I'd start another thread for the budget readers. The idea was to see how cheaply a turbo setup could be installed and how much power could be expected without breaking anything. All the work was done by students at the Blairsville, PA Wyotech campus. The results were pretty amazing... An article is due out in the Jan 2011 "Auto Enthusiast", but here's a quick summary.

What we are working with here is a 350 Chevy 4 bolt with cast crank, powder rods, 9:1 cast pistons (may be hypers), and Edelbrock e-tec 170 heads. Cam was a .501 / [email protected] 110 LSA hydraulic flat tappet. Basically Edelbrock's 360hp crate combo. The engine has Edelbrock Pro-Flo (Magneti Marelli) port injection with a 4bbl TB. The ECU was swapped for a FAST XFI stand alone, as the Edelbrock unit is not compatible with boosted engines.

N/A engine dyno baseline was 375hp / 360lb ft. We scrounged a Holset HX35 turbo that came off a Dodge Cummins pickup. The turbo was plumbed to a set of block hugger headers with a custom Y pipe. A Tial 38mm external wastegate was used, as the stock internal gate controller could not be adjusted to safe boost levels for a gas engine. The turbo was set up to blow through the TB with a Turbonetics carb hat. The 27lb/hr injectors were swapped for a set of 43s.

We decided to limit boost to 15psi, and crossed our fingers... . All pulls were made from 2500-6500 rpm.

After some tuning we ripped off a pull at 487hp /487lb ft. on 93 octane Citgo. Intake temps were getting out of hand, so we plumbed in a stock Dodge Cummins intercooler. That change (and some more fuel) netted a best pull of 527hp / 605lb ft. The best part: the turbo acted more like a supercharger, crossing into boost at 2000 rpm(!) and making 15psi throughout the pull range. The engine made over 500lb ft. all the way from 2500 to 6500 rpm.



The other best part: With some careful shopping, the turbo setup (less ECU) can be duplicated for just over $900 including all exhaust components AND an intercooler!

That's 150hp and 250lb ft. of useable power for less than a grand. Pretty good value I think!

[exwestracer]

So on to the update...

Since we found another Holset HX35 laying in the parts room, we decided to see just what this stock bottom end will survive...we are going TWINS this time around, with dual 4bbl TBs on a tunnel ram (again it was laying around from a past project...). We also swapped the cam for something a little more turbo friendly. We installed a Comp grind with [email protected] and a 114 LSA. Lift dropped into the .460 range, so we are putting a set of 1.6 Comp rockers on to get back to just under .500. We will actually be putting the single turbo setup back on first to see how the 2 camshafts compare power-wise.

I'll keep you posted...

[Wicked]

I love seeing this kinda stuff. Junkyard setups that is.

[PhillipM]

Yeah me too. I think it is becuase I would never do something like this... But secretely wish I would. Kinda like riding that scooter when your buddies aren't around! Haha

[DartorDemon]

Thats so cool. I really want to do something like this.

[exwestracer]

Well, we just did the pressure map for the HX35 on squirrelpf.com. Turns out it is a tad small for our application...but 2 of them are perfect...

[shmoov69]

Wow, I thought that two would be pretty big and have quite a bit of lag.
Good luck! Tell us what goes first! LOL!

[Z06killinSBF]

Nice, and I have a Garret GTP-38 from a Powerstroke just hanging out at my house...........

[exwestracer]

Wow, I thought that two would be pretty big and have quite a bit of lag.
Good luck! Tell us what goes first! LOL!

Us, too. It was truly amazing how quick it spooled... I think 2 might just be a little "laggier"...

[WS6]

Oh man this sounds fantastic! I really want a very quick spooling turbo setup for my LT1. This sounds like it may be a path I could venture on to. Please keep us updated as I'd love to follow this closely. Just to verify, these are engine dyno numbers correct?

[WS6]

Oh and is there any chance we can get some dyno graphs at some point?

[John Wright]

The other best part: With some careful shopping, the turbo setup (less ECU) can be duplicated for just over $900 including all exhaust components AND an intercooler!

That's 150hp and 250lb ft. of useable power for less than a grand. Pretty good value I think!

That is cool.....so any of these diesel truck turbos will work?

[exwestracer]

That is cool.....so any of these diesel truck turbos will work?

Uhhh...I didn't say THAT...lol.



We figured the airflow requirements for the 350 were in line with the 5.9 Cummins at lower rpm, which turned out to be exactly the case (plus we had a couple Holsets laying around). The turbo ran out of legs a little early just because the diesel never needs that much air. Garrett's website has some excellent articles on turbo sizing.

http://www.turbobygarrett.com/turbob...o_tech101.html

I'd think a single from a larger pickup engine would do a little better on top end.

WS6: Yes, those are flywheel HP numbers. I believe it would be an excellent choice if you are not looking for huge top end power. Obviously much more top end power can be made with a single turbo than what we achieved, with the usual tradeoff of bottom end torque and spool time. Stay tuned, we should be back on the dyno soon with the new cam combo and possibly a more realistic intercooler setup. I do have the dyno power graphs, but I'm not sure they can be converted into a format I can post. I'll check into that tonight if I get a chance.

[WS6]

Thanks Ray. I'm looking for broad torque that comes on early. Basically, if I could come up with a positive displacement turbo system I'd be so happy. I'm not a fan of waiting for a turbo to spool which is why I don't like pro-chargers either. Yeah, top end power is amazing but a pro-charger and the typical turbo build style is not what I'm after. I know I might end up making some compromises but I'm still confident I could build a turbo system that would meet my needs without getting crazy. After all, 500hp/500+ ftlbs isn't too hard and that's basically my goal.

[exwestracer]

I know I might end up making some compromises but I'm still confident I could build a turbo system that would meet my needs without getting crazy. After all, 500hp/500+ ftlbs isn't too hard and that's basically my goal.

I can guarantee you that much is possible...

[exwestracer]

Basically, if I could come up with a positive displacement turbo system I'd be so happy. I'm not a fan of waiting for a turbo to spool which is why I don't like pro-chargers either.

A picture I saw last night got me thinking, and I did some rambling over on the turbo forum this morning. Doesn't pertain to this thread, but you might find it interesting...

http://www.theturboforums.com/smf/in...topic=144162.0

[WS6]

I've thought about compounding a pair of turbos in order to really stretch the power band out. Diesel trucks are starting to do this with amazing results. The new F350s are compound turbos. It's going to stay on my mind but I believe it'll be too much overall for my simple street car. Thanks Ray

Trey

[shmoov69]

Definately NOT simple! Compounding is tricky from what I hear.

[exwestracer]

Looking back on it, I titled that other thread incorrectly. My idea there was to use a small supercharger to get some torque output and some exhaust energy, and then cut it out of the system and use only turbo boost for higher HP. I may even attempt this on the "no-buck" engine if the twins take some spool time. We should be able to find a couple small Eatons and adapt them to a Vortec truck type manifold lower half.

Hehe, from one cast-off turbo to twin turbos and twin Eatons....that would be fun! ...

[WS6]

Hellion racing, I think that's right, has a twin turbo setup for the new Shelby cobras that keeps the factory Eaton blower on the engine. So basically, they have enacted your idea already.