Turbocharging a non-turbo motor

[crimsonride]

I've been looking into installing a turbo on my snowmobile. Two things that you need to watch out for are intake air temperature (air heats up as it's comressed) and a lowered compression ratio. These are two of the contributing factors to detonation which is your major destructive factor when turboing your motor.

 

[Too Far]

Greg,
Dan Houlton converted his amigo 2.6 four to a turbo motor. Very similar swap to what you would have with a 22re. He was able to use parts off of an impulse for the basic pieces, but he had to figure out a lot on his own as well. The 2.6 has 8.6 CR and I think he gets 19 psi or so. Works well and has held together for several years. I'm sure he could give you some pointers.
www.houlster.com

 

[SuperRunner]

One of my friends was working on something like this... he was using a huge turbo from a semi, making it belt driven & was going to run it on a SBC. Except he couldn't figure out where to put the turbo! AFAIK, it didn't get any further than that. :-\

Well, I can tell you this, that probably won't work.

Turbo's run 80,000 RPMS+

 

[SuperRunner]

Greg, go for it? What turbo you going to use?

Just don't run over 7psi, and you will be fine. MSD makes a timing retard just for this too. You will probably want to run lager injectors, but then you will need and AFC, and a WB02...$525 for the combo. Get some 7MGE injectors, they are pretty easy to find, then tune. Another option may be, is to find if someone makes a thicker metal HG. That will help drop your comression ratio. Then bump up the boost, run an IC, and there you go. Anything 7psi or less, I wouldn't bother with an IC.

 

[cheapzuk]

http://www.bgsoflex.com/megasquirt.html

Why don't you just build one of these and use a wideband o2 sensor so you can fine tune it for all ranges. They have an option for a MAP sensor that will work under boost for turbo applications. That is just another method of doing it.

 

[4x4phil]

I've owned a ford 2.3 turbo mustang, and a 300zx. I also know very well the guy with the turbocharged 2.5 yj. He runs a stock motor with a t-3 turbo from a t-bird. Keeping your motor stock with a turbo gives you good low end torque for crawling, but plenty of power for freeway speeds and spinning those big tires. I have a lot of friends that have done custom turbo kits to their motors, ranging from 5 psi to 25 psi. I've also seen a lot of blown head gaskets. One thing has remainded constant. If you don't try to push over 5 lbs of boost you can run the turbo to the motor with no add-ons. No fmu, no high flow fuel sender, no bov, no timing retard, and your motor shouldn't ping at high rpms. My 2.3 mustang had no bov and It ran 7lbs stock. But to go any higher I would have needed it. Your fuel injectors can handle 5 psi also. This makes it easy to dial in your turbo. It's just a matter of plumbing the pipes. 5 lbs is good power. Most superchargers boost about that much, and just because a turbo can boost more doesn't mean you should. At 5lbs you don't get too much of a power surge so it'd work well in technical crawling situations. Just make sure that when you turbo charge a motor all your vaccum lines are in and snug. The pressure boosts the entire vaccum system and sometimes blows off a line or two. Keep it simple. Plumb in the turbo. Set the wastegate at 5 or 6 psi. Install the tubes from the compressor to the intake, if you want to plumb in a bov that's cool but not entirely necessary. And you have a very simple setup that gives you a lot more power at high end and leaves you with a manageable low end. And it won't screw up your motor, or computer, or fuel injectors. It'll make your rig reliable with a lot more power. Ps. My turbo 300 zx ran just 5lbs boost stock, and it really got up and went. And one last thing. Exhaust pressure needs to remain consistant. You can run duals, but you can't run just one off of a couple pipes. If you're turbocharged all exhaust outlets must pass through a turbo of some type. Otherwise the differences in back pressure will ruin your motor. Intelligent turbos on suvs "I think" are the future of rock krawling a 4wding.

 

[jamesgeologist]

Dual Turbo Setup

Maybe a dual turbo setup like this one? Couldn't you use 1,076 ponies??

 

[TurboMinivan]

If you don't try to push over 5 lbs of boost you can run the turbo to the motor with no add-ons. No fmu, no high flow fuel sender, no bov, no timing retard, and your motor shouldn't ping at high rpms.

At best, this is very poor advice. At worst, it will be very damaging to the engine in question. Quite frankly, a typical computerized engine which is naturally aspirated--particularly one which doesn't use a MAF sensor--will not magically add extra fuel to compensate for boost. Try it and you'll go lean and/or detonate... and the results won't be pretty.

I have a lot of friends that have done custom turbo kits to their motors, ranging from 5 psi to 25 psi. I've also seen a lot of blown head gaskets.

Blown gaskets, eh? Fascinating. I have personally watched people try setting up 5 psi without addressing the very real need for extra fuel. It's caused engine damage nearly every time. It's only a head gasket if you're lucky; it can shatter pistons (or worse) if you're not. If you care about your engine at all, please do not try it.

Your fuel injectors can handle 5 psi also.

Maybe; maybe not. Even a mere 5 psi of boost will require approximately 34% more fuel. To get it from stock injectors, you need to pull out a calculator and do some serious math to determine your injector pulse width (as a function of time) and compare this to your current injector duty cycle. If you're lucky, you may be able to alter the injector pulsewidth (only while under boost) to provide the additional fuel. HINT: the injectors won't magically do this on their own.

Another way to do this--and it's quite a bit easier, actually--is to adapt to a boost-referenced fuel pressure setup. In this way, the fuel pressure rises in response to boost pressure which, in turn, provides the extra fuel needed to match the increased quantity of air entering the engine. HINT: the fuel pressure won't magically do this on its own.

5 lbs is good power.

Yes, it certainly is. When set up correctly (with the proper air:fuel ratio and with a good intercooler) it can net you 1/3 more power and torque from your engine. That's a significant gain by any measure.

At 5lbs you don't get too much of a power surge

Perhaps, perhaps not; it depends heavily upon which exact turbocharger configuration you choose. This is another aspect of the beauty of turbocharging: you can decide where to create your torque band. Do you want a 2000 RPM stump puller? How 'bout a sweet mid-range spread that feels very similar to your current engine, only more so? Or, finally, maybe you'd like gobs of top-end for running out on the salt flats? You can easily end up with any one of these scenarios.

One reminder: Corky Bell covers the whole fuel issue in his book Maximum Boost. He covers all the other issues, too. It's a great read.

 

[4x4phil]

turbominivan is right and I stand corrected. Air fuel ratio is definately the most difficult thing to dial in. In thinking back we've always either had to reprogam, or rechip the cpu, or add an fmu to compensate at 5 lbs. My whole point is that you can moderately turbocharge a stock motor without spending a million dollars doing it. And stock motors shouldn't be slamed with a ton of boost or you can kiss'm goodbye. Any stock motor can handle 5lbs of properly intsalled boost without having reliability issues. 5lbs is what I consider to be the best boost for the buck. And the safest for your motor. Less isn't really worth your time, and more requires a lot more modification. I'm just trying to find a happy median. Every system is different and will react differently to boost, and you will always have to figure out how to properly prevent detonation. But you have to admit that at 5lbs you don't run into too many problems.