Go Back  RX7Club.com - Mazda RX7 Forum > Tech and Performance > Race Car Tech
Reload this Page >

e-shaft weber jets good idea for endurance race rebuild?

Race Car Tech Discuss anything related to road racing and auto X.

e-shaft weber jets good idea for endurance race rebuild?

Old 02-01-16, 02:30 PM
  #1  
Full Member
Thread Starter
iTrader: (1)
 
Join Date: Jul 2004
Location: Bucks County PA
Posts: 232
Liked 2 Times in 2 Posts
e-shaft weber jets good idea for endurance race rebuild?

I am just about to put my GSL-SE 13b back together. I have crushed the rear pressure regulator and shimmed the front bypass as most builders seem to recommend. This should bump my pressure to ~90 psi.

My question is though, given the modified regulators is it a good idea to remove the e-shaft ball check oil jets in favor of the always open weber jets?

As mentioned this is my budget enduro chump/lemons car so while it is a racing application I am not going to be over-revving the motor but it will most likely live between 5-7k rpms.

My only concern is people seem to think having the weber jets takes oil away from the bearing in favor of the rotors....

Any experience here?
wallyrx7 is offline  
Old 02-01-16, 03:00 PM
  #2  
Lives on the Forum
iTrader: (9)
 
BLUE TII's Avatar
 
Join Date: Mar 2001
Location: CA
Posts: 7,070
Liked 145 Times in 128 Posts
My only concern is people seem to think having the weber jets takes oil away from the bearing in favor of the rotors....

Any experience here?


You have it backwards.

You press in the Weber jets (or buy the MFR screw in jets) to RESTRICT oil flow into the rotors for cooling so the rotor bearings get more pressure at high rpms.
BLUE TII is offline  
Old 02-01-16, 04:23 PM
  #3  
Full Member
Thread Starter
iTrader: (1)
 
Join Date: Jul 2004
Location: Bucks County PA
Posts: 232
Liked 2 Times in 2 Posts
Originally Posted by BLUE TII View Post
My only concern is people seem to think having the weber jets takes oil away from the bearing in favor of the rotors....

Any experience here?


You have it backwards.

You press in the Weber jets (or buy the MFR screw in jets) to RESTRICT oil flow into the rotors for cooling so the rotor bearings get more pressure at high rpms.
So I bought the screw in weber jets from Atkins. Have you run a motor with this modification?

Just wanted to know if anyone has done this with success.
wallyrx7 is offline  
Old 02-01-16, 06:24 PM
  #4  
Lives on the Forum
iTrader: (9)
 
BLUE TII's Avatar
 
Join Date: Mar 2001
Location: CA
Posts: 7,070
Liked 145 Times in 128 Posts
No, I use the Mazda Factory Race oil jets

8553-11-411





which are basically the same thing, but just a whole new screw in oil jet.

Your oil pressure will be lower at idle because they are always open unlike the production oil jets where the spring pushes the ball against the oil hole in the e-shaft at low rpm so the rotor receives no cooling oil (faster warm-up) and then the ball swings out of the way from centripetal force as engine rpms rise.

Your oil pressure will be higher at high rpms (though still limited by oil pressure regulator) as the race oil jets have a smaller orifice than the production ball check-valve ones.

This is why people mistakenly say the oil pressure decreases.

-----------------

Its like saying what flows more a 90mm throttle body or a 60mm pipe?

Well, depends on if the throttle body is open, closed or somewhere in-between.

The production rotor oil jets are rpm throttled.
BLUE TII is offline  
Old 02-02-16, 08:57 AM
  #5  
Full Member
Thread Starter
iTrader: (1)
 
Join Date: Jul 2004
Location: Bucks County PA
Posts: 232
Liked 2 Times in 2 Posts
[QUOTE=BLUE TII;12022203]No, I use the Mazda Factory Race oil jets

8553-11-411





Those are exactly what I have. Thanks for the help here.

OK I think I will put them in then. I understand the lower oil pressure at idle but I suppose my main concern was that given I'm not building a 9k rpm motor, as like I said, the motor will probably live between ~4 to 7k that I might not even reach peak oil pressure at those engine speeds.

That makes sense that while they are fully open though, they have a smaller jet size to make up for the loss in pressure.

Thanks.
wallyrx7 is offline  
Old 02-02-16, 12:36 PM
  #6  
Lives on the Forum
iTrader: (9)
 
BLUE TII's Avatar
 
Join Date: Mar 2001
Location: CA
Posts: 7,070
Liked 145 Times in 128 Posts
OK I think I will put them in then. I understand the lower oil pressure at idle but I suppose my main concern was that given I'm not building a 9k rpm motor, as like I said, the motor will probably live between ~4 to 7k that I might not even reach peak oil pressure at those engine speeds.

Oh, I see your concern.

You shouldn't have any issues there, my motors have been low rpm turbo motors.

From memory, on my set-up (all the wet sump oil mods) on a S5 13BT it would be maybe ~15-25psi at 800rpm idle(depending on oil weight, how watered down with gas and oil temps).

Revving 1,500- 2,000rpm pressure would quickly rise to the 40-60psi range.

and by 3,000-4,000rpm it was in the full 90-110psi range (race oil regulator).

If you held it near redline (8,000rpm) a while you could see the pressure drop a bit (which I always assumed was due to aeration).

Later I went to the FD pressure regulator (gave away race one to someone in need) and the behavior was the same but the peak pressure was more 90-100psi (not a lot of difference).

---------

I had a real problem with the oil pressure pushing the front cover away from the front side housing and the o-ring there getting pushed into the front cover and suck around the over-pressure relief valve. Once that happened oil pressure was a little lazier to build and often barely maintained 90psi (on the MFR regulator).

I never bothered to fix this when it happened (just kept racing the motor) and I never had oil system issues. So, don't worry if your oil pressure is a little lazier.

I fixed this issue by boring the old (mostly unused now) oil passage in the front side housing and putting a dowel in that fit into the front cover. So the o-ring was captured and could get pushed into the front cover.

I didn't want to plug that passage and disable the over-pressure relief valve as I like to get in the car and go without waking up the neighborhood idling to warm up the oil.
BLUE TII is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
RxFred
1st Generation Specific (1979-1985)
6
05-04-16 08:24 PM
teamafx
3rd Generation Specific (1993-2002)
3
01-14-16 04:14 PM
teamafx
General Rotary Tech Support
2
01-11-16 06:40 PM


Thread Tools
Search this Thread
Quick Reply: e-shaft weber jets good idea for endurance race rebuild?


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: