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Short belt to bypass power steering

  • Thread starter Thread starter Frank07GT
  • Start date Start date Oct 28, 2008
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Frank07GT

New Member
Nov 14, 2004
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Chicago Suburbs
Oct 28, 2008
#1
  • Oct 28, 2008
  • #1
Hello all.

I found an old thread which mentioned this old 5.0L trick for our 3V cars. I took it one step further tonight and wanted to share this cheap, easy, (and hopefully successful) mod with everyone.

Basically, you buy a shorter serpentine belt which bypasses the power steering pulley and two of the idler pulley on the front of the engine in an effort to cut down on the power loss through parasitic drag. Less drag = more power to the tires. Pretty simple. The prior thread listed a belt length of 88" which fits if you route the belt around the two idler pulleys near the power steering pump. I experimented and found a different route that eliminates those two idler pulleys, and drag (albeit minimal) that they provide.

Through a series of trips to my local Autozone parts store, I found the correct length belt for my 07 GT. The 65 inch belt fit my car perfectly. It should be noted I have the Steeda underdrive pulleys on my car which may differ slightly from the length a stock car would use.

The Autozone part number is: 650K6, which will be a pretty universal part number across different brands since the first part: 650 - identifies the length (65.0") and the 6 at the end identifies the 6 ribs of the belt.

Steering the car at slow speeds takes some effort, but is certainly possible as you maneuver around the parking lot at the drag strip. Although not a huge drag, the power steering pump when spinning at 6K RPMs likely uses up at least a few HP that can otherwise be used to move the car forward. It only takes a few minutes to change the belt once at the drag strip. The belt retails for $16.99

I'm going back to the track tomorrow night. I'm hoping the few extra HP gets me closer to my goal of 12.99999999 in the 1/4 mile. Last week (without the belt) running my 20" Shelbys with Sumitomo street tires, I managed a couple 13.1s with the mods in my sig (link to video in my sig).

I'll let you guys know how it turns out.

Frank
 

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walter

Founding Member
Aug 13, 1998
1,054
0
46
Houston TX
Oct 29, 2008
#2
  • Oct 29, 2008
  • #2
Great find, it would be nice to see some dyno numbers before and after the belt to see what was picked up.
 

kooldawg6

mine works really well and can take a fair amount
Aug 31, 2006
1,679
2
38
Central VA
Oct 29, 2008
#3
  • Oct 29, 2008
  • #3
Thanks for the word on an even shorter belt as an option.
I will be trying the short belt next season for sure! Talking with Ron Leonard (spyder7724) of Leonard Racing (Spydershaft), the short belt is usually good for a tenth on its own! If you want to take it a step further, you can get an electric water pump and ditch the belt altogether for a single burnout/pass before the battery starts losing power. That netted Ron yet near another tenth. No wonder he can get his N/A auto GT into the 11.8s
 

Frank07GT

New Member
Nov 14, 2004
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Oct 29, 2008
#4
  • Oct 29, 2008
  • #4
I used to use a short belt on my old 5.0Ls. Whenever I raced the car, I would switch the belt. It was always worth a tenth of two in the 1/4 mile. The same principle should apply to our cars.

Gotta love cheap mods!
 
K

kevanp

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Aug 23, 2008
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South Jersey
Oct 29, 2008
#5
  • Oct 29, 2008
  • #5
Thank You

thanks for opening this topic!!

I have been hunting around for specifics on the shorter belt P/N.

Does anyone have a p/n or length for the belt on a car with stock pullies?
 

Frank07GT

New Member
Nov 14, 2004
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Chicago Suburbs
Oct 29, 2008
#6
  • Oct 29, 2008
  • #6
Well my SOTP dyno tells me the short belt made a noticeable difference. I noticed much easier tire spin and the car seemed to accelerate a little quicker.

The bad news is that I wasn't able to prove the advantage due to the poor track conditions up at my local track this evening. My 60' times were awful (2.2X) on each run due to poor traction, plus I was spinning the tires halfway through 2nd gear. GRRRR

I guess I'll have to wait until spring to do a before / after test again.

I would like to get the chance to test both the stock and short belts on a dyno to see that the actual measurable difference is.

kevanp, The size I mentioned (650K6) would probably work on a stock car. If not, it will be very close - perhaps 645K6 or 655K6. Good luck!
 
K

kevanp

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Aug 23, 2008
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Oct 30, 2008
#7
  • Oct 30, 2008
  • #7
Thanks
 

onebad95

Sherriff of Bling King County
Jul 22, 2002
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At the end of the track waiting for you !!
Oct 30, 2008
#8
  • Oct 30, 2008
  • #8
I tried this theory back in April on the dyno and got 4.5 hp out of the short belt on back to back runs on the dyno. It was a solid 4.5 through the whole curve. I always run the 88.5" belt at the track. Now, with the skinnies up front you hardly know it doesn't have power steering.
 

Frank07GT

New Member
Nov 14, 2004
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Oct 30, 2008
#9
  • Oct 30, 2008
  • #9
Well, there you go: 4.5 HP for $16.99!

Compared to so many other aftermarket products, that's a pretty good dollar/HP ratio

Thanks onebad95
 
T

TGJ

New Member
Mar 30, 2005
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Oct 30, 2008
#10
  • Oct 30, 2008
  • #10
I don't know what a PS Bypass belt is worth in RWHP, but I do know it is worth .15 in the 1/4 and 1 MPH with my car. I verified that the last time it was at the track...

I use the 88.5" Bypass belt.
 

bigcat

start with the upper hole, and if more traction is
May 1, 2005
3,015
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79
7200 feet
Oct 31, 2008
#11
  • Oct 31, 2008
  • #11
can you post a diagram showing the belt route with the 66" belt?
 
T

TGJ

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Mar 30, 2005
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Oct 31, 2008
#12
  • Oct 31, 2008
  • #12
bigcat said:
can you post a diagram showing the belt route with the 66" belt?
Click to expand...

It is the same as with the stock and 88.5" belts but also bypasses the pulleys beside the PS. I tried my Thunderbirds PS Bypass belt on my Mustang today which is 66" and it works as well...
 

Frank07GT

New Member
Nov 14, 2004
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Oct 31, 2008
#13
  • Oct 31, 2008
  • #13
Here is a crude Paint picture of the belt routing. The red line depicts where the short belt differs from the stock routing.
 

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bigcat

start with the upper hole, and if more traction is
May 1, 2005
3,015
1
79
7200 feet
Oct 31, 2008
#14
  • Oct 31, 2008
  • #14
thanks!
 
K

kevanp

New Member
Aug 23, 2008
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South Jersey
Nov 7, 2008
#15
  • Nov 7, 2008
  • #15
I just tried this trick tonight.

I have stock pulleys and an 07 gt . Used 680K6 for $17.

1/2 inch breaker bar, screwdriver and a printout of the belt path diagram. 10mins.

Easy job! Thanks for the help!!!

Track sucked tonight and 92% humidity. Worse than usual times so I have no feel for what the belt did.
 

Frank07GT

New Member
Nov 14, 2004
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Chicago Suburbs
Nov 8, 2008
#16
  • Nov 8, 2008
  • #16
 
K

kevanp

New Member
Aug 23, 2008
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Nov 8, 2008
#17
  • Nov 8, 2008
  • #17
Frank07GT said:
Click to expand...

having the full size printout of the diagram you provided saved numerous cursewords frank. much appreciated.

So did the 3 guys holding flashlights wondering what I was doing lol
 

Frank07GT

New Member
Nov 14, 2004
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Chicago Suburbs
Nov 9, 2008
#18
  • Nov 9, 2008
  • #18
Kevanp,

I'm glad it worked out! I forgot to mention, if you unbolt the coolant reservoir from the top of the radiator (2 10mm bolts), you can lay it on the driver's side of the engine compartment (leaving the hoses attached). This only takes a minute to do, but allows much easier access to the accessories.

I know, too late now! You might try that next time.

Frank
 
B

BLKNED

Member
Jan 27, 2008
67
1
9
Nov 9, 2008
#19
  • Nov 9, 2008
  • #19
If your going to put on a shorter belt then wouldn't it be worth some more power to bypass the a/c pulley too or is it not worth it with the a/c turned off anyway?
 

Frank07GT

New Member
Nov 14, 2004
22
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0
Chicago Suburbs
Nov 10, 2008
#20
  • Nov 10, 2008
  • #20
I'm not sure if the belt routing would work out that way. The way I set mine up, the tensioner pulley holds the belt similar to the stock setup.

The A/C (when not turned on) offers very little drag anyway - similar to an idler pulley.

Good point though. Maybe one of us can be even more resourceful and improve upon the belt path I listed.
 
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