Is it worth the money to SC the 16V 4.5? I understand an S4 or even a 32V, but I can't imagine pulling ponies out of the 16V 4.5. For that kind of money you might as well buy a 32v motor. But it sure does look cool on the 16's! I got the "You might as well drop a vette motor in there and SC it". Although it is cool, my father brought me up a porsche man.

 

the 32v will be even more expensive. finding a good one, sorting out the issues it may have.
convert the ecu to the 32v, wiring harness and then a SC?
you will be cheaper off doing the 16v and supercharge that

 

I know one Wisconsin 16V has plans to pump ho Vortech SCer up to 14psi "to see what happens." I applaud his willingness to experiment. On the plus side, 4.5L engines are pretty cheap! Maybe it'll last a week, maybe a year, nobody knows.

 

I really can't see why a 4,5l should have problems with 14psi if intercooling, fuel and ignition is under control? Ok, the wedge design of the heads are probably not the most effective, but sure 14psi on 8.5:1 compression is not rocket science?

 

You're right. It's not rocket science, but I don't think anyone has done it yet on a 4.5L (and I'm not sure if he's running an IC setup or not ). Should be interesting...

 

so , you're saying the engine would prolly be in one piece for a month?

 

I can! The problem is that the pistons are not forged so they are not meant to handle high boost. Just as Andrew said, the US 16V engines are very cheap so why not try it. At 14 it should be faster than most of the boosted 32Vs.

 

Now I know why my ears are ringing....
951's use the same head design, 20+ psi doesn't seam to be an issue with proper engine management control.

As for forged pistons others have mentioned. TMurphy's 600+hp S4 is using stock, non forged pistons in his 32V. With proper fuel and controlling timing 14psi is not very high by today's boost standards. With forged pistons you can really push the limits so I'll be playing it safe with this motor at first, go from there.

When Tim and I started to design a setup for my 16V based off his kit many years ago, the goal was high boost. Reason why I opted for the IC that I'm using. A one off design that fits where the factory air box is located.

I know the title of the thread is a twin screw.....I'd be very, very leary of that setup on a 16V unless you have some way to reprogram the computer or conver it to MAF (like John Kuhn did with his turbo). Why do I say that? The L-Jet is very lathargic down low, likes to go lean (even under vacuum). Not a big issue with the vortec but all that boost at 1,500rpm.........not sure the L-Jet system will react fast enough to fuel it. I have nothing against any form of forced induction. But you have to look at the big picture to figure out what will work. I have no doubt DR has the knowledge and skill to make a twin screw 16V. Just curious how he's going to do it.

 

I'm not sure he is going to do it. Probably costs too much.

 

Hacker, the biggest difference between the pistons on the s-4 and the 16v cars is the thickness of the material between the top edge of the piston and the 1st ring gland. Deetonation can cause this to fail much earlier than on the later pistons. Add to that the fact that there is no knock detection or means to remove timing under knock conditions and you have a problem. Call schmoopie and discuss the piston issue with him, thats where I got the info. I also think there may be a fairly easy/cheap way to take out some timing under knock. I plan on trying it down the road but maybe you can give it a shot sooner. I know you have the guidance of the engine and boost guru's up in your part of the country.

 

With the same compression my 4.5 has, Tim & Todd have tested S4 pistons up to 24psi with zero issues (with the pistons). So 14? on the early ones....who knows.
Yea, this is one nice feature on the S4 motors.
Jean-Louis was running 6psi - non intercooled with 10.4:1 CR on a 928 race car. He has now added an air / air IC - I'm sure the boost will also go up. This is a 4.7 euro motor.
One thing you are forgetting (or didn't know) there is a very, very easy way to dail back timing under boost on the duel vacuum port distributors.
This trick came from John Kuhn, something he learned while building the TT 928.

Like I told andrew - I have two 4.7 liter motors and one 5.0. If I grenade this 4.5 I'm not going to shed a tear. It's a test mule. You won't know the limits until you break something.

 

 

If it is done correctly, yes why not? If it is correct that he is not going to use a IC and probably no proper engine management, nope... Then I too have to ask why?

This guy in Sweden got into some problems after a while on 16psi, but he did not use a IC.
http://my928.kicks-***.org/Fries/index.php

 

I've looked at this site and I can't read it but I thought he was running approx 9psi from the MAP log. Do you know if he increased the boost from what the MAP log shows? I have an AutoRotor that I'm installing on a 1980 16V and I'm having trouble finding injectors that fit the stock rail.

 

I'm very interested to see how a twin screw setup will work as well?