mark kibort

the injector seats are quite a bit different. probably be better to extrude hone the US runners and use your plennum, while trying to fit a TB from the aftermarket world. (ie 3.3" diameter across the Throttle plate)

I dont know if those runners can adapt to the US injectors. the seats are different, and the rails mount to the runners in the injector style from 85-85 euro

Weissach1982

How much bigger are the intake runners on a Euro than on a US model? And if anyone has been checking out my other topic about the AUX fan/smog removal topic, can you actually feel the difference in gains by removing the pump and adding fan/fans?

This question is off subject and i've searched the archives(didn't see anything except auto-5spd swaps) for it and didn't want to start another topic seeing as ive started two already,other people need to have their time on the front page. Anyway, I was wondering if its worth it and is it possible to swap a 4spd auto as a direct replacement of the 3spd.?
Thanks,
Cory J
82 Weissach

mark kibort

the intake runners for the US 84 are 1.5" diameter. the euro is 1.6. Ive heard that the early runners are 1.4 if so, I have a set of US runners that I can sell you cheap. Ill check on the comparisons as I have Scot's Weissach 82 runners and my 84 runners for comparisons.

not any gains you can feel with the removal of the air pump (very very light load and mininal inertia. belt driven fan is in the 1-2hp range MAX.
Now, as far as bliping thottle feel, all this inertia adds up. the fan, the pump can be effectively a lot more, not on dyno hp , but on bliping the throttle hp. (ie very fast reving, compared to dyno run or actual 3rd gear accel, that takes over 5-9 seconds depending on your engine hp)

mk

Jon F

I was the one lucky enough to get first dibs on John's Euro intake, which has already arrived. Since he didn't have a Euro throttle body to go with the runners and plenum, I wrote to a few breakers to see if they had a Euro throttle body available. Mark Anderson of 928 International suggested that the '85-'86 US 32v throttle body may be a good replacement as it is similar in size to the Euro throttle body. I went down there to compare the 16v US throttle body to the 32v US version, and it looks like they will swap except for the differences in the throttle switch. I haven't yet measured the stock 16v US throttle body, but the 32v US throttle butterfly is approximately 3" or 76mm in diameter. I picked up the 32v throttle body and will be attempting to put it on my car today or tomorrow using a harness that I have made to adapt the newer throttle switch to my car. There will also have to be modifications to the vacuum system and the vacuum limiter will have to be eliminated.

I did a baseline dyno run today and should have an "after" run by next week. My car has a hollow cat, a K&N filter, and is missing the intermediate muffler, but is otherwise stock.

mark kibort

this is your baseline for what car?? (engine and what mods)

200Hp ???? thats pretty darn good. I know my 84 4.7 was pretty fit when I did a 242rear wheel with all the euro stuff (up from 200 at the rears with headers and exhaust just like yours. but do you have headers?)

You should seee 40hp for the intake stuff. the euro 4.7 throttle body is 3.3 " diameter at the TB plate. the 85-86 is pretty close to that. the US is tiny!!!!!! 2.5" at the throttle plate.

on the throttle switch, dont worry about the fuel cut off. just the 70% full throttle part is important. so, you only have to worry about 2 wires.

also, the new throttle switch (integrated in the TB vs the micro switches of the US type) will get in the way of the oil filler vent. this is an easy fix by going out of the bottom of the US "U" with a different hose. Pull the fitting out of the U and mount thread in an elbow. then, use that part you pulled out to mate the new hose to the exsisting oil filler hose.

How does the 85 throttle body off the 32 valve fit the US "U"? the US "U" has a 4 bolt pattern. I suppose you could make a plate for any type of TB and then linkage would be the next minor mod. Ive done a few of them, so I know some of the details. One thing for sure, big power gainer!!!

vaccum lines are pretty self explanitory. vacuum advance at part and full throttle for timing and vacuum for idle for the fuel regs. (ie two different ports in the venturi of the TB. (ie narrowest part)

mk

mark kibort

By the way, man , you twisted that poor old motor up high 6600rpms?!!!!

this is a great example of why it pays to shift at 6000rpm and not a bit farther with a stock gear box. with a 1.33 or .73% drop in gear changes except 5th, 6k shift brings you to 4300, which gives the best average HP . any higher, and your average goes down and you LOOSE HP to the wheels in a race condition.
MK

toofast928

Bravo Jon F lets us know if the 32V Throttle body can be adapted. I measured the throttle plate on my L USA 1982. = 65mm ugh! Too small. and I agree with Mark the plate is acting as a restriction. A 32v Throttle bore of 73-76mm is more like it and bottom end power should remain.

Also I'm atempting to convert the AFM to MAF. The inlet of the AFM is square and 55mm. I located a MAF from a Ford mustag 5.0L. It fits the 928
"U" perfectly.

mark kibort

should remain the same?? it does. my torque was 235 and with the euro intake it went to 236 and the hp went up from 200 to 242.

Now, as far as the adaptation. Ive tried this already and have a euro intake bottom that mates to a MAF. I also have a finely machined adapter that would mate the mustang or any 3.5" maf to the US "U" as there is a little o ring that you want to have a good fit, plus be able to mate to the stock Euro air box. If you want this set up, let me know. it would include the adaptation ring to fit the US "U" o ring and the euro bottom of the air box.. I got this done by Huntly racing, but the MAF system conversion didnt even come close to functionally working *(wrong voltages) also , BE careful about MAF sizes. its not just the diameter, its the through put area. so, most 3" MAFs will have almost the exact same area as our little AFMs when you subtract the hot wire housing. if you do go aftermarket MAF, go with a 3.5" MAF> Ive done all this,and taken great notes. dont re-invent the wheel.

so, I stayed with the AFM, and it still put out 292rear wheel hp out of an AFM.

MK

Let me know if you are interested in the euro bottom and huntely racing custom U adapter step down ring.

GoRideSno

Mark,
I have a throttle body that has a 80mm throttle plate. Because it is bigger than the S4 throttle plate (75mm) I assumed it was a Euro TB. It uses the same style throttle switch as the 85-86 and the S4.
What is this?

If it is a euro and anyone really needs It I may be willing to trade it out for something else soon.

Andy K

toofast928

Mark,
What exactly about the AFM to MAF voltages were you unable to adapt?
Need to convert the MAF signal .9mv to 5v. to the AFM 3v-7.5v.
I have the slit second ARC2 box with 4 adjustable pots to increase the voltage. Works for the 944 and 911 guys. I figure the voltage plot would be dialed in to where the full voltage of the MAF peaks out (5V) at 3000 RPM. From their the ECM defaults to RPM speed for air/fuel ratio.
I haven't run the set up on the car yet. Maybe the ECM is just too slow to interpret the MAF?

Jon F

Update: I've pulled out the "U" section to port it so it looks like I've got an extra day's work or so. The exit at the throttle body end is 73mm, or about 2.9", which is the size of the opening of the US throttle body (which as many have noted, is only 65mm at the throttle plate). Like Mark said, I have to modify the oil separator air line to move it out of the way of the 32v throttle position switch, but there doesn't look to be enough room to use an elbow so I'll be teeing into the line that goes to the auxiliary air valve or the one that goes to the air valve for the air conditioning/charcoal canister control valve and capping off the existing outlet. That doesn't look like it will be much of a problem.

The 32v 928 uses a different throttle cable system, I suppose, because it only had a ball for pulling the throttle from the front of the car, rather than from behind as in my 1980. I ended up swapping the 32v throttle linkage for the 1980 version which required punching out the stud from the inside and swapping nearly all the springs and levers to the 32v body. This sounds like more work than it really was, but as an added benefit, I'll get to keep my non-operational cruise control.

Some pictures: (sorry, forgot to take a before picture of the standard 32v throttle linkage!)

'80 throttle linkage on the 32v body.






Here's where you can really see the size difference.


Standard US on top, Euro on the bottom.


Standard US on top, Euro on the bottom.

Weissach1982

Wow what a difference the Throttle body is, the US version looks as if were the size of one on a Honda Civic. How much bigger are the runner ports on the Euro compared to the US?
Will I have to buy new Intake boots, c-clamps, along with gaskets for the runners...for everything to mount up?
Also, how much porting is needed to make things bolt up?
Thanks,
Cory J,
82 Weissach

mark kibort

Yep, thats the one that DONT work.

the ARC2 box works on 944 0-5 volts but not the AFM 3-4 to 8 volt system

I tried and could barely get the car to start !!!!

sent it alll back ,except for the nice adapter so that i could do it someday. now, I have an S4, so no need for the adapter and the euro air box. that will fit an early 928 US perfectly

mk

mark kibort

runners are about the same external size, 1.5 vs 1.6"
the plennum mounting to the US vs euro is the key thing, so you need a euro plenum. the 85 throttle body has the same bolt pattern? if so, there is another way to do it. porting is only needed on the "u" that mounts on the bottom of the throttle body.

mk

Jon F

Mark, I sent you an e-mail about porting the "U" section. I'm not clear on what material has to be removed after opening the throttle body portion of the "U" to 3.3" or so. Did you port the "U" all the way through or just blend it outward from, say, halfway, to the throttle body opening?,