This thread was the inspiration behind this:
http://www.supraforums.com/forum/sho...7&page=1&pp=25
The supra featured in that thread runs a 88MM turbo which is probably capable of around 1500rwhp. Normally such a turbo would be almost undrivable on the street -- not this car. He won't disclose the details yet, but it's running very high compression (his tuner mentioned domed pistons) to spool the turbo. He makes 30PSI at 5300RPM at stock bore (3L). The only downside is you must run high octane all the time or run a very safe tune on pump gas. (His car has two fuel tanks: when he goes WOT it switches to VP Import fuel. This setup has never been done before and required modifiying the internals of the AEM EMS.)

Anyone willing to try such a setup on their daily driver?

 

Try it, sure. Pay for the cost no.

 

No one does it because the detonation comes into play with pump gas.

 

im confused- you need to move more volumes of air to spool at lower rpms, how can higher compression help increase exhaust velocity? The displacement will not change, right??? You have a more "violent" explosion, this just seems to cry "crank walk" to me- cant you just burn a higher grade fuel to increase compression? (more air of course)

 

Increased static compression, within the limits of the knock threshold of a particular engine, will make more usable low end torque to spool the turbo quicker.
It is about volumetric efficiency. In the lower part of the rpm band volumetric efficiency is at its lowest point, Depending on the cam profile of course and throttle position. With increased static compression the same amount of air and fuel can now do its work more efficiently by developing torque quicker in the lower part of the rpm band. Again with the proper sized camshafts and conservative duration specs, dynamic compression will certainly come close to static levels quicker.
The main problem with running this type of setup on the street is based soley on the effective octane level we have available to us.
With race fuel 12,13 even 14:1 static compression ratios are used regularly on race cars that have forced induction.
So in theory the exhaust energy will increase along with temperature if the Air and fuel are squeezed into a smaller quench area and chamber volume.

Crank walk IMO is a completely different issue alltogether.
my 2 cents

 

You beat me to it! I couldn't have said it better myself. That adage "there's no replacement for displacement" still rings true. I know several people running stroker kits on their DDs. In most situations they have improved reliability because they are using stronger than stock internals. not to mention less lag because of improved volumetric efficiency.

 

There was a guy here named Renee von Richthofen, yes he was a relative of that von Richthofen. Anyway, he had a fully decked out and track prepped S4, big turbos, built motor, the bulletproof $12k tranny from Champion Motorsport. Before the car hit the track, he flew over the engineers and techs from Audi to dial in the car at Moroso....anyway, that car had 2 fuel tanks with a switchover for race gas, he was running Motec.

Just because a "tooner" hasn't done it, doesn't mean the big ballers haven't done it.

 

You can up the compression on the 4G63, but if you do I would do a complete rebuild and get the absolute best parts / mechanic to do it. High Compression + High Boost = increased chance of BOOM.

 

This car's not going to be any fun on the street running on pump gas.

 

3240, look at the setup again. The setup that mentioned the S4 - two fuel tanks to switch between race gas and pump gas mode with a switch - is nothing like this setup.

He has the equivalent of two seperate fuel systems. As soon as the car reaches a certain throttle position it switches - ON THE FLY - to the other fuel system and the other map. As soon as the throttle is let off it switches back to pump gas and the other fuel map!

The ideal setup would be to do a stroker (not too much stroke, you can overstroke) and use the best parts. He has a Full-Race G55 custom turbo-kit, 2.2L billet crank, custom titanium rods being manufactured now. The problem is, and it wouldn't be as big as a problem with AWD, is traction with this much HP.

 

The AEM EMS has all the features to run a redundant fuel system and transition to an alternate fuel via rpm and load. Its the secondary injection feature. Im currently building a fuel system like this for my evo8 to run gasoline for idle/cruise and run methanol under high boost. Nothing special has to be done to the EMS for this to be used on the street.

 

ok...but look at it this way....the fuel switch will not be in the blink of an Eye....there is somehow gonna be a lag and you will be able to feel where the fuel switch will be...so if its so called switch on the "fly" i think that really wont work....both fuel lines are not continuously loaded with fuel, therefore the closed tank would have blown a fuel pump already...so with that so called switch theres going to be a delay from when tank 1 stops sending, and tank 2 starts...so IMO i dont think its switch on the fly setup...or if it is...i would like to know what the hell they used

 

Yes both systems are full of fuel and pressure. As soon as he hits a certain rpm and load level the system switches to the secondary injectors fuel map and is now using those injectors.

 

ahhh....ok....thats all new to me...never heard of running to seperate fuel tanks b4...sorry

 

how do get more air with higher compression? I understand higher compression will create more "explosive detonation", but spool faster? also, you could run a higher octane fuel without raising compression, to get higher hp- i used to build honda race bikes, so I can definately say that raising compression will net more hp, I just dont know about the spool up-
if this is true, everyone just mill the head a few thousandths- good to go....