Alright I have some questions on turbocharging mainly mounting, lubrication, and cooling. I want to fabricate my own twin low mount turbo system. Questions are do most people run water cooling to their turbos? Is this a good idea to do? When low mounted is a basic oil pressure and return all that is need, will I run into flow problems? Next how much does it matter how close the turbo is to the manifold? Yes I know there are front mount and rear mount turbos and I know the difference. But I am saying approximately 2.5-3ft from manifold collector to turbo inlet. Trying to get my homework done thanks!

 

Also! In the case of there being 2.5ish feet of tubing between manifold and turbo where is the optimum placement of the wastegate? Closest to the turbo? Does it matter?

 

if your turbos are mounted low your going need a oil scavanging pump on the return. Turbos will respond quicker when mounted close to the engine.

 

Alright. If the turbos were sized correctly it would probably be unnoticed as far as spool up and response don't you think? My purpose of a low mount is to have a smooth Low temp overall operating system.

 

I would probably say with 2.5ft distance from the collector there should be a very slight loss in response.

turbos mounted under the hood add heat to underhood temps. you could wrap or coat your exhaust tubing to cool down temps.

 

You can compensate alittle with turbine size and turbine housing to get better spool with turbos farther away from engine. Need some heat to build exhaust energy so wrap the pipes good to keep heat in. You can reduce some of the heat that radiates to components in the engine bay but its still going to get hotter than a naturally aspirated setup. Wrap and heat shields will help with heat control.

Low mount like said above will need a scavenge pump on the drains. Can T the drains into a single pump as long as its enough flow capacity. I'm trying the turbowerks exa pump which flows 2.6 gpm. Hope thats enough for my twins. We shall see.

Waste gate can be within the 2 ft charge pipe before the turbo and after the manifold collector. Best control likely will be with the wastegate closer to the turbo but shouldnt really matter.

 

Alright. How low of mounting would qualify for having a pump? I assume to the point where the oil cannot let gravity do its thing and run back into the pan?

 

yep, just about. The drain must be higher than the pan, but also need enough vertical drain line angle to allow oil to flow freely to the pan. Too far forward in the engine bay will leave the drain line 45 deg to the pan or worse. It may go flat for a few inches. Not good for oil draining. 45 deg straight to pan may work if the line is large. Larger is better -10 or -12. But any flatter than 45 deg, it may hurt draining.

 

Alright, I can understand all this. So really you want a straight shot back the pan. Alright what about the whole water coolant lines on the turbo? Does anyone even use any of that?

 

i would think the wastegate should be closer to the throttle body to fully empty the charge pipe .

i was asleepo when i wrote this i ment bov should be closer to the tb , the waste gate has to be between the turbo an the exhaust .

 

Thats on ball bearing turbos... dont need to spend money on those for a V8 turbo setup unless you want to. Journal bearing types have worked fine. Just need oil supply in, and oil drain out. No water lines anywhere. But if you needed them, try to find a waterpump with a aux outlet you can tap into. Or take it form the intake manifold if possible, there is usually a port for the TB bypass/water valve line. Perhaps tap into that and run water to the turbo.

 

I see now... Should I decide to build my own manifolds for this project which gives less problems? The heavy gauged log type manifolds or the stainless tubular design?

 

logs with heavy material likely be best for longevity and no risks for cracking but i havent had a problem with my mild steel header tubes. 16ga. Have heard guys use thin stainless with no cracking problems too. Just dont hang a turbo off the end. Brace it up. Thick logs or thick schedule weld els can support some weight and are best for hanging turbos off them.

 

So how much weight does all that add? Two turbos, two wasyegates, two log manifolds, intercooler... my car doesn't hook the way it is n/a with a posi, what's adding 200+ horse and possibly a hundred plus pounds to the front gonna do to me?

 

Put the battery in the rear to offset and enjoy enjoy the heck out of whatever the results are!

 

Haha true. I've got the battery and nitrous in the back finally.

 

Its pretty heavy.

2 turbos are about 20 lbs a piece. wastegates are about 2 lbs total I think. manifolds on my car appear to be about 10 lbs total. Not sure, i'm not a good judge of weight

Intercooler is 25-30lbs. All the cold side/hotside piping, flanges/couplers adds up a good 15-20 lbs I bet. I used mild steel on everything. Aluminum coldside would be half the weight.

So right there is almost a 100 lbs on the front end. I noticed my front wheel well gap being much tighter now and I even replaced the factory hood with a fiberglass one.

 

Alright. How much of a pain is it to get boost right on twins? Beings there is two of everything...

 

Easy as putting on the same wastegate to each side, T the vacuum lines together and run them to the intake manifold plenum. Top wastegate port gets open atmosphere air, bottom port goes to the intake manifold

Very simple

 

Alright. I like the sound of that. I'm kinda torn on what I should run... I've also been contemplating a single t76 ball bearing..

 

Single can be cheaper overall since theres 1 of everything instead of 2. May have more flexibility to mount 1 turbo than 2. Only need 1 turbo manifold instead of 2. Just run a shorty on one side, and cross over pipe to a custom turbo manifold. can be a simple log with an input pipe entering into the turbo manifold log section either at the rear or front by the turbo flange. Thats the best bet so you dont have exhaust being thrown into the other bank's cylinders who are trying to expell gas at the same time.

 

Yeah true. So I've decided to run manifolds flipped forward and tig my own stainless piping and flanges. From what I've read 304 ss should be sufficient. Is this a good choice?