The Twin Screw Thread
#1293
Supercharged
Rennlist Member
Rennlist Member
Join Date: May 2002
Location: Back in Michigan - Full time!
Posts: 18,925
Likes: 0
Received 63 Likes
on
36 Posts
Oh yeah... forgot to mention that I have already spoken to DR about this and he's talking to the manufacturer of the pulleys to find out if they screwed up or if by chance there's a different kind of belt we're supposed to be using. My guess is that the mfg screwed up.
Can't blame DR. I know I would have never thought about checking that especially since he's never encounted this issue.
Can't blame DR. I know I would have never thought about checking that especially since he's never encounted this issue.
#1294
Supercharged
Rennlist Member
Rennlist Member
Join Date: May 2002
Location: Back in Michigan - Full time!
Posts: 18,925
Likes: 0
Received 63 Likes
on
36 Posts
Originally Posted by 928drvr86.5
Any news on when the early 32v 928SP Twinscrew setup will be available?
#1296
Under the Lift
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Originally Posted by Rick Carter
Good info, details, details, details. Good folks in WI; not like they have a monopoly but they certainly deserve recognition.
I agree wholeheatedly with Rick. Tim & Todd deserve major kudos for figuring out and fixing 2 serious problems for you in short order.
I guess the pulleys on Andy's old kit are fine, as I'm still on the same belt after more than 18 months and almost 20 k miles now. Also, with the repositioning of the throttle and different cabling, I was very careful to check WOT as well as idle when I made a bracket to improve the throttle cable path in Andy's kit. But this still brings up a very good point... Right now George Suennen is only getting about 6 lbs of boost at high altitude with his Murph kit. We have been focusing on the belt. We need to check that he is getting full wide open throttle, even though his throttle body is stock. Then we should look at the possibility he is restricted in the air intake area - an issue with the limited space in front of the Vortech for a good intake path. I had noticed but not thought much about that restriction, but your post raises it in my mind.
Thanks for posting this with all the details. I would never have figured out the pulley thing as quickly as Tim and Todd.
#1297
Supercharged
Rennlist Member
Rennlist Member
Join Date: May 2002
Location: Back in Michigan - Full time!
Posts: 18,925
Likes: 0
Received 63 Likes
on
36 Posts
Actually, we were going to tap the airbox and hook up an analog vac/boost gage to see what, if anything, was going on there in terms of restriction. If we had done this, it would have shown increased vacuum as the boost fell off. But lucky for me Todd's eagle eyes spotted the TB not opening.
Huge kudos to those guys! I'd send them a fruit basket, but they live on beer, brats, and cheese. Fruit is only used as a garnish.
Huge kudos to those guys! I'd send them a fruit basket, but they live on beer, brats, and cheese. Fruit is only used as a garnish.
#1298
Rennlist Member
Originally Posted by Andrew Olson
I would say it will happen as soon as Mr. Speake finishes the SharkTuner for them.
Oh good........ no pressure then ! Aaaaaaargh !!
#1299
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Originally Posted by Andrew Olson
Huge kudos to those guys! I'd send them a fruit basket, but they live on beer, brats, and cheese. Fruit is only used as a garnish.
#1301
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Originally Posted by John Speake
>>>>>>>>>>>>>
Oh good........ no pressure then ! Aaaaaaargh !!
Oh good........ no pressure then ! Aaaaaaargh !!
#1303
Supercharged
Rennlist Member
Rennlist Member
Join Date: May 2002
Location: Back in Michigan - Full time!
Posts: 18,925
Likes: 0
Received 63 Likes
on
36 Posts
Attention "sealed" Autorotor owners
Ok all you Autorotor dudes! I've been quietly dealing with some issues with my setup. I'm 99% sure this has nothing to do with DR's setup per se, except that I've been having some oiling issues with the Autorotor itself.
The Problem:
I would loose boost at about 4500rpm. This was evidenced by the boost gage falling off. When I was in Wisconsin for the tail gate party (good time BTW!) we noticed that the belt was getting cut by the pulley and it was literally turning to dust. The inside of my engine bay was covered with dust. I wiped it up, we got a new belt, and "fixed the pulley." (see above #1290). I also had a ‘slight’ manifold restriction that we discovered and fixed.
Upon testing, I was making full boost ~ about 7.8 psi! I was very happy. But the joy didn’t last. The next day as we were having some fun, I saw the boost was falling off at about 4500 rpms and would be almost flat (1-2 psi) at redline. Every time I thought the tension was low or it was a pulley issue, etc. I was very frustrated.
The Solution?
Oh yeah, let me also add that I’ve tried various belts: Dayco, Gatorbacks, Gates, etc each with it’s own unique issues. Well, since I’ve been back, I tried another new belt but this time I noticed that I had a lot of oil on the SC bracket which led me to think that maybe some of this oil was fouling the belt. Makes sense doesn’t it? So I cleaned everything up with brake clean and installed the new belt. Took it out for a quick spin last night and voila! 7.8-8.0 boost! Now that’s what I’m talking about! So I think it’s pretty clear to me that the oil that’s coming out the snout is fouling the belt/puleys.
Well, in my search to a solution to my issues I came across this thread:
http://www.nsxprime.com/forums/showt...t=76454&page=2
It doesn’t appear that I’m having the oil on the bottom issues like this guy did, but the spray that he refers to is the same as mine. But this thread really peaked my interest.
Also, DR had said to fill the oil on the SC up to the 2nd line, but according to this document, maybe lower is better.
http://www.kennebell.net/techinfo/ge...chargerOil.pdf
So anyway, I think I have a solution.
#1, lower the oil level in the SCer.
#2. Today, I bought myself a molded rubber elbow to go on the breather-screw of the SCer, to which I will connect a coupler and then some line to direct any oil vapor away from the belt.
We’ll see if this solves my issues, but I wanted to throw this out for anyone else experiencing issues with the “sealed” autorotors. Unfortunately, I have little time the next 2-3 weeks to drive the car, but maybe I can get it out a few times next weekend.
The Problem:
I would loose boost at about 4500rpm. This was evidenced by the boost gage falling off. When I was in Wisconsin for the tail gate party (good time BTW!) we noticed that the belt was getting cut by the pulley and it was literally turning to dust. The inside of my engine bay was covered with dust. I wiped it up, we got a new belt, and "fixed the pulley." (see above #1290). I also had a ‘slight’ manifold restriction that we discovered and fixed.
Upon testing, I was making full boost ~ about 7.8 psi! I was very happy. But the joy didn’t last. The next day as we were having some fun, I saw the boost was falling off at about 4500 rpms and would be almost flat (1-2 psi) at redline. Every time I thought the tension was low or it was a pulley issue, etc. I was very frustrated.
The Solution?
Oh yeah, let me also add that I’ve tried various belts: Dayco, Gatorbacks, Gates, etc each with it’s own unique issues. Well, since I’ve been back, I tried another new belt but this time I noticed that I had a lot of oil on the SC bracket which led me to think that maybe some of this oil was fouling the belt. Makes sense doesn’t it? So I cleaned everything up with brake clean and installed the new belt. Took it out for a quick spin last night and voila! 7.8-8.0 boost! Now that’s what I’m talking about! So I think it’s pretty clear to me that the oil that’s coming out the snout is fouling the belt/puleys.
Well, in my search to a solution to my issues I came across this thread:
http://www.nsxprime.com/forums/showt...t=76454&page=2
It doesn’t appear that I’m having the oil on the bottom issues like this guy did, but the spray that he refers to is the same as mine. But this thread really peaked my interest.
Also, DR had said to fill the oil on the SC up to the 2nd line, but according to this document, maybe lower is better.
http://www.kennebell.net/techinfo/ge...chargerOil.pdf
So anyway, I think I have a solution.
#1, lower the oil level in the SCer.
#2. Today, I bought myself a molded rubber elbow to go on the breather-screw of the SCer, to which I will connect a coupler and then some line to direct any oil vapor away from the belt.
We’ll see if this solves my issues, but I wanted to throw this out for anyone else experiencing issues with the “sealed” autorotors. Unfortunately, I have little time the next 2-3 weeks to drive the car, but maybe I can get it out a few times next weekend.
#1304
Andrew,
They really should not leak at all.
All of the leaking twinscrews that I have seen were caused by leaking seals. (or the odd loose hose on some Millenia sourced units) Most of the seal leaks were caused by improperly supported snouts (ie, bracket was not supporting snout at tip).
A couple were caused by mediocre assembly work done by a certain domestic licensed subcontractor who manufactured twinscrews in Fresno...
I have no idea where your snout support is, I can't really see it in the pics. If it is not directly behind the pulley, it is less than optimum. Non-optimum snouts work, but if one were to measure it, there would be snout flex - which prematurely wears seals. Worn seals leak oil. And eventually wear other things at an accelerated rate.
The closer to the tip of the snout the support bracket is, the better the snout support bracket works.
It is also entirely possible that your issue may lie elsewhere.
Good Luck,
Greg
They really should not leak at all.
All of the leaking twinscrews that I have seen were caused by leaking seals. (or the odd loose hose on some Millenia sourced units) Most of the seal leaks were caused by improperly supported snouts (ie, bracket was not supporting snout at tip).
A couple were caused by mediocre assembly work done by a certain domestic licensed subcontractor who manufactured twinscrews in Fresno...
I have no idea where your snout support is, I can't really see it in the pics. If it is not directly behind the pulley, it is less than optimum. Non-optimum snouts work, but if one were to measure it, there would be snout flex - which prematurely wears seals. Worn seals leak oil. And eventually wear other things at an accelerated rate.
The closer to the tip of the snout the support bracket is, the better the snout support bracket works.
It is also entirely possible that your issue may lie elsewhere.
Good Luck,
Greg
#1305
Supercharged
Rennlist Member
Rennlist Member
Join Date: May 2002
Location: Back in Michigan - Full time!
Posts: 18,925
Likes: 0
Received 63 Likes
on
36 Posts
Greg-
Here's a nice pic. You can see the support for the snout. Just in front of it is the "breather" screw. But from what I've read this will allow oil to escape if there is sufficient pressure wich is often dictated by oil level.
Here's a nice pic. You can see the support for the snout. Just in front of it is the "breather" screw. But from what I've read this will allow oil to escape if there is sufficient pressure wich is often dictated by oil level.