Old & New

Hey Brendan,

Nice out-of-the-box thinking.

Tony

Latest issue of HOTROD details the Twin Screw FORD GT engine..
Some specs:

500Hp @ 6000rpm
500ftlb @4500rpm
400ftlb @ 2000rpm

8.3:1 CR "nominal" (not sure what they mean by that..anyone)
90.2mm bore
105.8mm stroke (seems like a lot doesnt it???)
5.4l displacement

67.5mm Main journal dia
53mm Rod journal dia
169.1mm rod length (6.66in)

37mm intake valve
32mm exhaust

11.2mm intake valve lift...on 242' duration
11.5mm exhaust valve lift ...on 247' duration

32lb/hr injectors

Lysholm Twin screw supercharger displacing 2.3L..max rpm 14500

315kg weight

356-T6 alloy block
dry sump oiling

Actually a very good article on it. Heres a good one.
" During the exhaust manifold cracking test, the engine runs at full load WOT for 150 hrs to generate the heat in the manifolds"

"air exiting the blower at 300'F is cooled to about 170'F as it passes through a honeycomb air to water intercooler encased in the upper and lower halves of the intake manifold"

Warren928

Interesting Brendan-
An externally oil lubricated S/C with separate cooler and pump. Anyone have ideas on what kind of pump one could use for this application?

The question is, how much in tempurature will the cooler supercharger actually drop the compressed air? The same question goes for engine compartment tempurature, how many degrees could it actually effect the air traveling through an aluminum duct heated at say maybe 120-140 degrees? Maybe I am too low with my under the hood temps, has anyone actually tested this theory?

What would be the best setup for dropping engine compartment tempurature on a daily driver?
My Z had two hood vents but I like the clean look of the 928's hood, does someone make a hood for high cooling?

Tony

BTW..someone mentioned that "Muscle Mustangs & Fast Fords " had a great article on Twins Screw SC's.

They do! A VERY GOOD READ!!

picked mine up at Borders. Nov 2003, Vol 16, issue 11. the sticker says display until 10/28/03... FYI

BC

We will have to ask those who actually have an on-the-car setup currently: How does the oil get from the pan to the head unit back to the pan? Is it already pressurized somehow? I would also make sure the SC headunit was painted matt black.

If we were to imagine a pump and cooler system for the oil-fed head unit, I think we would need to know the original system, and were the oil goes in the gearcase, and how it comes and goes.

I'm thinking this process would make the headunit that much more robust. I really don't think it would add that much more complexity.

GoRideSno

Warren,
Z recently posted on another thread that tests had shown that the temp under the hood of the 928 was 85-90F above ambient. Tests showed that intake air was heated up about 30 F. I assume these tests were done w/ the stock airbox.

Tony,
Good info on the GT40 twinscrew system. The animation in the link looks strangely familiar. From the specs the GT40 engine is similar to the CL55 AMG, same displacement, same compressor, same power. The CL55 has a 10.5:1 CR though. From the figures you have listed the final combustion chamber temp of the GT40 is about 1140 degrees F. I'll be picking up both of those issues today.

Andy K

Z

I really don't think that the oil cooler for the supercharger would make much if any difference, and wouldn't be worth the trouble. The whole supercharger housing will be at least as warm as the underhood temperature. That's around 170F or more. The oil going to the supercharger is only going to the bearings in it, so it's only a relatively small portion of the whole supercharger housing that's exposed to it to pick up heat. Under boost the supercharger is going to heat the air up a considerable amount because of compressing it. Under normal conditions the oil temperature wouldn't be really that hot compared to the temperature that the supercharger already was.

If your car has the louvers controlling airflow into the nose of the car, locking those in the open position has been shown to reduce underhood temperatures about 5F and intake air temps about 10F. Completely removing the flap system makes an even bigger difference. A lower temperature thermostat will also bring those temperatures down some too.

CMW

Andy,

Speaking of the WHIPPLE, it should be in tomorrow... or heads will roll.
I still have to get the Bell FMU... So off to e-bay.
Give me a call on the cell or at work tomorrow.

Chris W

Tony

Another interesting bit of info.
this is regarding a swap of superchargers on a Ford SVT Lightning from a roots to a twinscrew

''Simply replacing the Eaton M112 roots blower with the more efficient twin screw design upped the power to the tune of 60 horsepower"


No wonder these are all going a dime a dozen on ebay these days...al the Ford guys are updating to the twin screw and Kenne bell kits!


we are itch'n to see a Dyno run Andy and what area is under that Hp/Tq curve.

GoRideSno

Chris,
I'll call you tomorrow. Plan on putting in some late nights over the next 2 weeks. Have they shipped it, did you get a tracking #?


Tony,
I like d the MM&FF articles the most. Man, what about that "03 Cobra maxing out the chassis dyno with over 1200 ft/lb rwtq. WOW! It had very few mods - switched to a twinscrew, larger injectors, computer chip, 130? shot of nitrous. I was surprised to see the Eaton M112 would put out 18psi and was pushing the car to the mid 10s in the 1/4. There is more potential w/ the Eaton than I thought. It's clear that the twinscrew is where it's at though. 9.59 1/4 mi, no internal mods. Thats TT Supra fast!
We'll soon have a few dyno sheets to post.

Andy K

LukeSportsman

I have one of those silly Ford S/C trucks and I must say they are impressive considering the head flow rates Suck. Boost is obviously only a sign of resistance and there is plenty of it going through the stock intake and heads combo. We also run cast manifolds and exhaust back pressure is no friend of blowers.

I've got buddies running in the mid 7's in true street trucks in the 1/8th miles (these differ from the "street/race" trucks in the mags, these are real drivers) I don't race mine nor have any real interest in racing a 5,000 lb truck, but still impressive in their own rights.

I can only imagine how much hp these same (now sitting on the shelf) Ford blowers could support in front of good heads! These trucks make the 928 look like swb 911's in the weight department. Most guys have found that the point of dimensioning results seem to be 15lbs. Going above 15 seems to heat up the air unnecessarily and shorten blower life. Though an intercooled 15 psi is going to add twice the airflow as stock minus heat and other losses would stil yield, what, a 75% increase in hp! But how about torque, my Ford (5.4l 2 valve ohc with restrictive heads) has like 450 ft lbs about where you'd let the clutch out on a 5 spd!

Warren928

So it sounds like my car, which has no louvres wouldnt need much adjustment for under the hood temps, and cutting vents into the hood for the sake of cooler charge air would be marginal at best.

The oil cooler separate from the engine sounds like it might have marginal results as well.

Probably the easiest way to receive marginal to moderate results in intake air tempurature drops besides an intercooler would be to configure a new ram air sucking only cold intake air, and on my S3 I am considering running a 4" air tube from the supercharger to either in front of the condensor or under the headlight assembly.
If it goes under the headlight assembly then I will have to setup an airscoop fitting from the lower valance brake cooling duct.