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Motorcade is right...

Running an air-to-air intercooler to the nose will give you massive turbo lag. Running an air-to-water intercooler is more efficient, but then you're running about 25 feet of tubing under the car that's filled with water (at 6 pounds per gallon). The turbo WILL generate a lot of heat and considering the placement of the Toyota engine, the exhaust manifolds are pretty close to the rear trunk area, so you'd most likely lose your trunk. You would also have to design headers to work with the turbo and a lot of the thin-walled header material won't stand-up to daily use and heat generated by the turbo. Considering that this motor has 11.5:1 compression, I'd say that 8 PSI is achievable with VERY careful tuning, but I'm guessing 8 PSI will yield another 30 horsepower. Is it really worth all that trouble?

BTW, I think the picture of the turbo set-up on the S2 motor is from the passenger compartment looking toward the motor. So the intercooler in that picture really would be situated behind the driver.

Bob K.
 

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Bob, my thoughts exactly. just to argue semantics, though, the water has to weigh more than 6 lbs/gal, because JP-5 weighs about 6.8 lbs/gal, and it floats on water. Everything else is just like you said though, only heavier.

And let's not forget the extra hp consumed by the water pump to overcome the weight of the water and the friction as it resists flowing through the tubing.

I suppose if I was going to go to all that trouble (and I'm not) then I would put lower compression pistons in at the same time, so I could at least run some higher boost to make all the effort worthwhile. And then there's still turbo lag. No thanks. Engine swaps are cheaper and more effective, with fewer issues to sort out. And even that is way down the road. I need to wear out the toyota lump first.

Cade
 

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The kits for the Celica GT-S are producing 250WHP at 8 PSI with the stock compression. I saw the dynos. I think you are right an air to water intercooler would be complicated unless it is fit in the rear compartment. It will be interesting to see if a tuner can work-out the fitment and heat management problems. I came across one tuner that managed to get 230hp NA with a cold air intake, exhaust, and ECU tuning. The Lotus exhaust is supposed to be top notch. Maybe a cold air intake and ECU adjustment will get us there. That would put the HP output in the range of the K20.
 

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Re: Motorcade is right...

rtking said:
filled with water (at 6 pounds per gallon)
1 litre of water weights 1 kg
1kg = 2.2 lbs
1lt = 0.264 US gallons

Therefore 1 gallon of water weights about 8.3 pounds.

(Waiting for my Elise is driving me crazy, I've got to do math problems to pass the time!)
 

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Discussion Starter #25
More Turbo thoughts

A couple of ideas to ponder:
Several folks said that they like the feel of the NA motor better. I understand, but let's be realistic, the Toyota engine with VVT is gonna have its own turbo effect when the came kicks in. I have heard these on the dyno and they are like 2 totally different motors. Secondly, I have an M3 with a turbo. If you turbo a high compression motor with a low-pressure turbo and you do it right it feels like a NA motor with the VVT cam kicking in much earlier. The high compression gives you throttle response and the lower boost gives you a more natural power delivery. The air-water IC seems to be the way to go.
Lastly, if 230HP is possible NA and it is not terrifically peaky, that would be pretty sweet too.
 

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Lotus Fury said:
I'm just hoping my 24" spinners will fit right cause that's just the way I roll.* :D
Word.
 

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The step in cams can be thought of somewhat like a turbo. But that only happens at one rpm point. And if the ECU is tune like the Exige you wouldn't switch back down for another 400 rpm. However a turbo has a bit of lag spooling up. As boost builds you get a bit of nonlinear power delivery. Power off then back on quickly makes for poor throttle response. Larger displacement motors running low boost will greatly mask that effect. It appears that Lotus/dealers are looking at a SC for the 230 hp range, may be better then a turbo for throttle response but not so good for high hp goals.
 

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Discussion Starter #28
Mo betta boost

I hope if Lotus does do an SC they do it right. Centrifugal units suck and roots blowers are too inefficient. The only way to do it right is with a twin-screw. I still contend that VTEC cars have "turbo lag" too. If you have ever driven one, they have like 25 lb/ft of torque at low RPMS.

How much does the Mazda Renesis Rotary weigh?:D :D
 

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I'll tell you guys what you need to do to get the no-lag turbo thing all sorted out: hypercharging.
You've seen those junkyard wars episodes where they build jet engines out of truck turbos right? Well, same basic idea. You hook up the turbo like normal, but add your own combustion chamber between the intake and exhaust manifolds. At idle you dump extra fuel in there to keep the turbo spinning, and the boost full on. When you open the throttle, you get instant boost, and you can turn off you extra fuel because the engine will feed the turbo. Just think, not only will you have the cool whine at the stop lights, but you'll save gas too because you don't have to run it all the time.

I've been an advocate of this for a long time, but for some reason no one has seen fit to try it on their ride yet. ;)
 

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Evl, what you're describing sounds very much like an ALS (anti lag system). It's routinely used on rally cars, and I have seen it on a street driven Subaru. Not for the faint of heart, though, they say that the turbos end up having a fairly short life span.
 

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Close to ALS. My understanding of how ALS works is that you retard the heck out of the timing, so that the gasses are still burning when they come out the valve into the turbo. I think its hard on the valves as well as the turbo. Having a separate air/fuel source for the hypercharger should allow you to design it for the right EGT at the turbo to keep the life reasonable. Aparently they did this on some WWII airplane engines. Maybe they couldn't take the ALS approach w/o digital ignition and FI back then, but I still think its a neat idea.
 

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Re: More Turbo thoughts

fzust said:
A couple of ideas to ponder:
Several folks said that they like the feel of the NA motor better. I understand, but let's be realistic, the Toyota engine with VVT is gonna have its own turbo effect when the came kicks in. I have heard these on the dyno and they are like 2 totally different motors. Secondly, I have an M3 with a turbo. If you turbo a high compression motor with a low-pressure turbo and you do it right it feels like a NA motor with the VVT cam kicking in much earlier. The high compression gives you throttle response and the lower boost gives you a more natural power delivery. The air-water IC seems to be the way to go.
Lastly, if 230HP is possible NA and it is not terrifically peaky, that would be pretty sweet too.
I couldn't disagree more. A turbo will give most engines 100+ lb-ft of torgue, and 100+ hp compared to their Na counterparts of the same displacement. Of course this is a different case for the Elise engine, but the 30 hp bump you get at 6000 RPm is by no means a turbo effect. My TT is putting out around 270ish hp and you fee the turbo kicking in hard at 3000. At about 3000 RPM I get 1.2 bar of boost (about 17-18 PSI).

Also, the NA tuning that is done on this motor usually makes increases in the 6000-8000 RPM area. Most tuning is done with the high lift cam, and any torque increases are miniscule. The only way to add a lot of power below 6000 is with FI.

I would love to add a turbo to the Elise, but it will cost a bundle, and I don't see the point of adding only 6-8 PSI. I would want to add 20 or so, and that means new rods, pistons, and everything else. I Will do the NA route probably too, as long as I can get a minimum of 25 hp. If it seems that a 25 hp gain is out of the question, then a supercharger will just have to do!
 

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Have you checked out what 8 psi in 2ZZ-GE is yielding on the new celica site? How about 270hp at the wheels. Low boost may be just the ticket. You could choose a small quickly spooling newer generation turbo to eliminate the lag and still produce enough umph to push the Elise into supercar territory.
 

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Eyelise- do you have a link, intrested in more details. Considering stock it's 180hp crank, to go 270rwhp, we're talking well over 100hp for 8psi, it's not likely a small turbo or stock motor.
 

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The link is www.newcelica.org. check out the forced induction forum. The kits are designed for stock internals. The best I read was about 300HP at the crank or 270hp at the wheels for the more heavily modified cars. 270hp at the crank with the straight bolt on kit from ? turbotechnics. Stafford design has a kit as well. Fitment will be the issue for the elise. I think it might require putting the turbo under the car and using an A-W intercooler.
 

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I actually saw the dyno from that very tuner. They used a PowerFC ECU. Unless it was fabricated it was indeed 230hp. unfortunately the benefits were all high up on the second cam and torque gains were minimal. I like that ECU though.
 

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That power output makes it sound more like a "3ZZ" kit. A 2ZZ-GE using the long stroke 1ZZ-FE crankshaft.

And I believe the "3ZZ" is commonly matched with the Power FC ECU.

Of course, you'd expect improved output at all rpm, not just top-end :confused:
 

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Discussion Starter #39
Larry B wrote:
Eyelise- do you have a link, intrested in more details. Considering stock it's 180hp crank, to go 270rwhp, we're talking well over 100hp for 8psi, it's not likely a small turbo or stock motor.





Agreed that is unrealistic, however theory isn't too far off. Most likely it has other improvements in the breathing like a CAI or better exhaust. Ideally 8psi should yield about 50% power improvement IF the turbo is efficient, the intercooler is efficient etc, etc. So 270 crank is plausible.

As far as the others' comments about "only 8psi", that is all you need in a high compression motor. Only when you have low compression do you need to make up the compression with boost.
 

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A "twin-screw" is this a Lysholm supercharger as once offered by Corky Bell for the Miata ?

These chargers are very efficient because they do not convert plenty of the precious crankshaft power into heat which has to be removed thereafter by a big charge cooler again.

But also the Eaton blowers have 2 screws and nowadays can make more than 0,8 bar.
Somebody has seen an eta- (efficiency- diagram ).

Lysholms, made in Sweden have been installed already into the Rover- Elise here in Germany. They require more space but are not as hot as an exhaust gas turbo charger, which BTW also does not work for nothing because it increases the pressure drop in the exhaust and by this costs some power gain .

Best solution would be a supercharger activated by the ECU via a magnetic clutch only when you need it.
But I doubt that some tuner has build such system for the aftermarket.

Please correct me in case I am wrong
 
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