Carl Fausett

I have read some posts on Jet-Hot coating the 16v intakes for looks and stuff - but I was wondering if anybody has documentable dyno numbers on before-and-after extrude-honing their intakes and the plenum. Before I part with $585 for extrude-honing, I want to know how many HP I can expect from the process.

Jay Wellwood

Can't say for sure the benefit of this process on the 16V intakes.

One 32V owner tried it on an S4 Intake with no measurable gains on the dyno before and after tests.

Quaz

I know on the US 16V manifold there are some gains to be had, but on the Euro manifold I am not sure. Mark Kibort might be the guy to ask this question. He has tried just about every combination of US and Euro parts together on a 16v motor.

John Veninger

Carl,
Haven't seen a dyno sheet, but read you should get around 12HP gain on a EuroS 4.7lwhen EH a EuroS intake.

Don't know what that means for your 79 Euro intake, which is smaller than the EuroS intake.
I think you'll get close to a EuroS flow with a standard set of intakes EH, but you TB is still small.
Don't know if it will make any difference on the supercharge setup since your forcing the air in.

Might be better to try and find a set of EuroS intakes and TB.
At that point gets some EuroS heads and cams <img border="0" title="" alt="[Wink]" src="wink.gif" />

Fastest928

We tested a euro S intake on a stock us 79 with no gains and loss of torque up to 5400 rpm.

Marc
DEVEK

Jim bailey - 928 International

But that means bigger is NOT always better ! or more to the point Porsche could have made the intake runners any size they wanted and they did . What works on a 300 hp high compression 4.7 with larger valves and more camshaft as confirmed by testing is too big to be efficient on a stock 4.5 (intake air velocity drops off the cylinders do not fill as well ) . Those who have dropped S cams into a stock 4.5 are often disappointed as well as they see less bottom end torque . Improving on the intake system is no easy task and is usually always a compromise between low end torque or top end horsepower (the S-4 intake Flappy helps do both ) . If Carl is talking about his turbo car ; as was mentioned before then smaller runners may be better . Stock 911 Turbo cars ran very small intake ports of 32 mm for more lowend torque efficiency until they made boost at which point intake tuning becomes somewhat moot . If you have pressure boost ...you have pressure and the cylinders fill easily it is no longer neccesary to wait for the air to fall into the void created as the piston drops down into the cylinder. The boost pressure has the air waiting to rush into the cylinder the moment the valve opens .

BC

BUT - Jim, if one were to slap a 5.0 block back onto the original 4.5 intake and heads, then EH or a Euro intake and TB WOULD be beneficial, as the "Air pump" that is the engine would need more air, right!

Jim bailey - 928 International

Once you start to modify the engine as you mention increase displacement from 4.5 to 5 liters then the cylinder swept area increases and it "sucks more" . The question then becomes where is it being restricted ; by the valve diameter , port diameter , lift and duration of the valve being open , intake runner diameter , throttle body size or all the above ?? These are all upstream now throw in some exhaust changes and it creates more questions . Unfortunately very few people have tested the result of changing just one item at a time . All I am sure of is a 5 liter is better than a 4.5 liter all else being equal !!

928ntslow

Interesting. Everyone has talked about it, but no one seems to be able to prove one way or the other whether certain swaps benefit the car.

I haven't installed them yet, but I have a set of Euro intakes with Euro throttle body, fuel regulators and a pair of MSDS headers. These will be installed on my US 1982 4.5 liter.

I expect to get a "positive" difference from these changes. A dyno before and after will tell me if I have wasted my time and money.

BC

AND jim, using that theory, then a bored 5.0 liter to 106 with sleeves and high comp(Or low comp for SCing) pistons will do EVEN BETTER.

<img border="0" title="" alt="[Wink]" src="wink.gif" />

Keith - Dude - you have been talking about getting those pieces on that 82 of yours for how long? A year or more? GET WITH IT keith!

If you do a dyno day for SoCal, I will go to that. I need to see if my headers made any different when coupled with a dual exhaust.
The FEELING is sure different with 4spds.

928ntslow

LOL...man do I know it!

The details as to why I haven't done it yet are too boring, but Hey, I'm gonna!

My plans are to do it in April. <img border="0" title="" alt="[Wink]" src="wink.gif" />

We have kicked around a Dyno day and will definately give you a holler when we do.

Randy V

I installed an extrude honed intake that I purchased from Jim Nowak, after the DEVEK mods to his car. While I primarily wanted it so I could ceramic coat it (Jet-Hot), and swap it with my original intake, I was also hoping for performance improvements.

I did no baseline nor after-install dyno testing, but the SOTP meter did register snappier low-end throttle response. Perhaps it was just the placebo effect.

In any event, I ended up with what I started out after (really just a shameless overture to show off my perty engyne ) :

<img src="http://www.momentoffame.com/snapshots/MomentOfFame/l16752.jpg" alt=" - " />

John Struthers

One more picture Randy,
And I'm comin'out there to steal those beautiful shiny pieces!
Hey, it would be cheaper for air fare than having mine refinished.
John S.
P.S. Now if you would just yank that fan/pulley mount and have it finished...It would really make my inter-state theft project worth while...