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Twin Turbo V6...cooling

3K views 79 replies 18 participants last post by  Animal 
#1 ·
Hi gang....i need some advice ;)
Im part way into stripping down and upgrading a cally V6 engine which is going in to a GTE. I have 2 T3 garrett turbos and a good friend that can make up the exuast manifolds for me to fit the turbos on each bank...the problem im going to have is the turbo that is at the rear of the engine will get ruddy hot..will one of the bonnet scoops work ok or will i have to introduce some type of air flow mod to the engine bay?

cheers :beer:
 
#30 ·
I've had discussions with ERL who make the Aquamist water injection kits. They have mentioned that many V6/V8 engines suffer from specific cylinder heat problesm not just GM. THey have created a water injection system that can inject more water into those cylinders that suffer form overheating than those that don't.

Could be worth investigating if your going the turbo route. Apparently Scoobies suffer from this problem so they run these special kits aswell.

May help :confused:
 
#31 ·
There are several issues to solve before turbocharging or supercharging a V6. Mine indeed was the 3.2 V6 supercharged (400bhp) and with nitrous (500 bhp).

1. Making extra cooling slots for the back cylinders as described above.
2. Use the later type 2.5 cylinder heads (e.g. vectra gsi with natrium filled valves), as the originals cannot withstand the increased heat and oilpressure.
3. Reinforce the conrods as they will simply snap.
4. Make stronger crankshaft bearings.
5. Use a larger radiator, and have the thermostat open sooner and the fan on earlier and longer.
6. Use a large inter-cooler (over 12 litre).
7. Use low compression pistons.

In the long run, the F28 will not be able to cope with the enormous torque. In my case up to 400 lb/ft. These are the basic rules, if you want to go over 350 bhp. I hope this helps.

Frank.

ps. The car has been broken, but the engine is still for sale! send me a pm.
 
#32 ·
Hi Frank,

Many thanks for the information

How did you reinforce the conrods? I've been looking at steel rods, but if there's a cheaper way.....

Cheers
 
#36 ·
Glad I could be of assistance. Don't hesitate to ask again.

I am selling the modified 3.2V6 engine with supercharger, intercooler, very fresh F28 gearbox, modified engine mounts, driveshafts, airco, radiator, all ducting, reprogrammed ecu etc. Plug and play basically. Engine has done about 6,000 miles, all including for GBP 10k.

Frank.
 
#42 ·
ideally something from emen, but I don't know how well suited it is to my concept. I want to run the turbo's feeding the supercharger which then gets intercooled, then gets fed into the plenums.

I've got the space to do it all, it's an interesting project, it'll be something new to do, it can be done in stages, and would make for serious controllable power. it won't be the cheapest project, especially on fuel costs, but it'd keep me interested.
 
#44 ·
if you do that, you're limited by the unboosted flow rate of the supercharger. it won't affect when thec come on boost, as thats governed by the exhaust flow, not the inlet.

The design has been run by by some bloke off eng-tips. All credit to him for doing it.

I have also fabricated my own twin-charge system on a small 4WD hatchback that I drive every day.

It combines the best of both worlds, the low end torque and instant response of a positive displacement supercharger, and the top end airflow and power that only a turbo can produce.

There was also a commercial kit available to retrofit a turbo onto the already supercharged Toyota MR2.

In my case it is basically a supercharged and inter-cooled engine in the normal way, with a turbo compressor feeding into the blower intake. By changing pulley ratios and exhaust a/r, you can make it behave either more like a supercharged engine, or more like a turbocharged engine.

Boost reference for the turbo wastegate sees the final boost after the supercharger, so it can control boost in the conventional way to the desired set-point. It is a great system, the only real objection to it is cost and complexity, and fitting it all in can be a challenge as well !

Nitrous oxide is a simpler system, but if used constantly can be a nuisance to keep refilling. However a supercharger just keeps on pumpin.....
shame there's no email address for the guy, as I'd be fascinated to find out more about what he's done.
 
#45 ·
Did you seriously think I'm wrong?

that's weird...

cheeky as well:p

Here's how it goes: the supercharger creates boost at very low revs (I assume a positive-displacement unit in your case, as it's the only one that makes sense)
This extra boost in turn results in more exhaust gases at very low revs, that help spin the turbos quicker.
The supercharger lowers the boost threshold.

In a proper setup the SC is disconnected at high revs, when the turbos are on-boost, so you don't have the parasitic losses.
After the whole thing is mapped the fuel consumption is nowhere near as high as you'd think.:beer:
 
#46 ·
Compound charging has it's advantages and disadvantages like anything else. The thing you have to ask yourself is wether or not you really need that supercharger there, with 2x T2 turbos on a V6 peak torque can be produced at around 2500 to 3000rpm. And that's not a figure plucked out of the air either, that's what the twin turbo Ford V6's perform like. Given that you have five gears and good ratios it is highly unlikey the power band wont be big enough.

I'd even go as far as to say with a single T3 on a V6 a supercharger would be almost redundant, as you well know I drive a relatively prehistoric single turbo V6 and I can assure you lag isn't much of an issue at all.

A compound charge system on a V6 would imho be a time consuming and unrewarding excersize, unless you were just doing it to learn and experiment. You'd only ever see the benifit of the blower when pulling away in fith at about 30mph any other time it will be more of a hindrence than anything.

If the engine was smaller or had a whopping great turbo then there's reason but with 2x T2's or with 1x T3 compound charging just isn't needed.
 
#48 ·
There's a guy (squeak) in the XROC who is running 12sec 1/4s with a 2.9V6 with 2x T2's and they aren't even being pushed that hard. Bear in mind just how much air a Cosworth YB can shift before you need a T4, you are talking over 450bhp, you would need some serious internal modifications before even considering that kind of boost.
 
#49 ·
JohnA said:
Did you seriously think I'm wrong?

that's weird...

cheeky as well:p

Here's how it goes: the supercharger creates boost at very low revs (I assume a positive-displacement unit in your case, as it's the only one that makes sense)
This extra boost in turn results in more exhaust gases at very low revs, that help spin the turbos quicker.
The supercharger lowers the boost threshold.

In a proper setup the SC is disconnected at high revs, when the turbos are on-boost, so you don't have the parasitic losses.
After the whole thing is mapped the fuel consumption is nowhere near as high as you'd think.:beer:
lol, any up ur own bung hole gen. Just cos you're old doesn't mean you can't be wrong. :p

I know how it works, I just disagree that putting the turbo's after the supercharger is a good idea, as it'd decrease the efficiency of the turbo having to suck through a blower.

any 'In a proper setup, you do it my way' Gen? :p lol
 
#50 · (Edited)
MWF said:
Compound charging has it's advantages and disadvantages like anything else. The thing you have to ask yourself is wether or not you really need that supercharger there, with 2x T2 turbos on a V6 peak torque can be produced at around 2500 to 3000rpm. And that's not a figure plucked out of the air either, that's what the twin turbo Ford V6's perform like. Given that you have five gears and good ratios it is highly unlikey the power band wont be big enough.

I'd even go as far as to say with a single T3 on a V6 a supercharger would be almost redundant, as you well know I drive a relatively prehistoric single turbo V6 and I can assure you lag isn't much of an issue at all.

A compound charge system on a V6 would imho be a time consuming and unrewarding excersize, unless you were just doing it to learn and experiment. You'd only ever see the benifit of the blower when pulling away in fith at about 30mph any other time it will be more of a hindrence than anything.

If the engine was smaller or had a whopping great turbo then there's reason but with 2x T2's or with 1x T3 compound charging just isn't needed.
Well, I'm keen on having good throttle respoonse and minimal lag at all points in the rev range. All the turbo cars I've ever driven have had crap throttle response, which is why I'm keen on supercharging.

I have 2 T3's at home, from the metro turbo. (1.3 4 cylinder engine). Given that each one will be effectivly on a 1.5 3 cylinder engine, I think they'll be fine, (time will tell) but I want better throttle response than they'll offer at low revs.

You know as well as me that there's zillions of different spec T3's out there, and just cos it's got the t3 housing doesn't mean anything without more detailed specs.

It'd be a top project as I can try it with just the turbo's, or just the supercharger, and then both. I'd be able to tell what setup I want.
 
#51 ·
That's fair play Animal, like I said it's it's in the name of experimentation then go for it. I just don't want anything to think they are going to see a great hike in performance from such an involved modification. I agree on the throttle responce front, you should try and have a go in a twin turbo 2.9 Sierra and see how that feels as it would be a good comparison.
 
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