Adjustable Fuel Pressure Regulator
Thread Starter
3rd Gear
Joined: Apr 2012
Posts: 3
Likes: 0
From: Pittsburgh PA
Adjustable Fuel Pressure Regulator
I just ordered some new injectors from FIC for my 91 6 speed. While I was doing that I wanted to put in an adjustable fuel pressure regulator. What brand do you suggest? My car is stock so I'm not sure if if an adjustable one would even make a difference. I did a search here and saw that Holley makes a good one but when i go on the Jegs and Summit websites I see one but they say it isnt for my car. I see Jet and TPIS also make one. Any help or advice would be appreciated. 
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
I just ordered some new injectors from FIC for my 91 6 speed. While I was doing that I wanted to put in an adjustable fuel pressure regulator. What brand do you suggest? My car is stock so I'm not sure if if an adjustable one would even make a difference. I did a search here and saw that Holley makes a good one but when i go on the Jegs and Summit websites I see one but they say it isnt for my car. I see Jet and TPIS also make one. Any help or advice would be appreciated.
..WW
Last edited by WW7; May 6, 2012 at 09:14 AM.
Safety Car
Joined: Aug 2009
Posts: 3,751
Likes: 275
From: Melbourne, Victoria, Australia
Hi the tpi loves 40 to 45 psi fuel pressure, i would not go above that pressure as the injectors will have to work harder.
The side effect you may find it idles rich but you will notice an improvement in performance.
The side effect you may find it idles rich but you will notice an improvement in performance.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
You may want to change the fuel filter before installing the injectors or adding a regulator.
For a stock motor, the factory regulator will work fine even if you are adding the Bosch III injectors from Jon. As mentioned, consider replacing the original diaphragm before going with an adjustable unit. Be sure to check the fuel pressure before doing the work to make sure there are no other issues.
According to the Summit page, the JET #61501 is listed to work on 85-91 L98 Corvettes. Go here and scroll down the list of cars to find the Corvette application. This is not a bad price considering it comes with free shipping.
For a stock motor, the factory regulator will work fine even if you are adding the Bosch III injectors from Jon. As mentioned, consider replacing the original diaphragm before going with an adjustable unit. Be sure to check the fuel pressure before doing the work to make sure there are no other issues.
According to the Summit page, the JET #61501 is listed to work on 85-91 L98 Corvettes. Go here and scroll down the list of cars to find the Corvette application. This is not a bad price considering it comes with free shipping.
Thread Starter
3rd Gear
Joined: Apr 2012
Posts: 3
Likes: 0
From: Pittsburgh PA
I just looked up the price for a new AcDelco diaphram. $170 is that right??? I could get a whole new AcDelco fuel pressure regulator for less. I see other companies make the diaphrams but in the past my car doesnt seem to like any other parts put AcDelco. Has anyone used any other diaphrams and had success?
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
I just looked up the price for a new AcDelco diaphram. $170 is that right??? I could get a whole new AcDelco fuel pressure regulator for less. I see other companies make the diaphrams but in the past my car doesnt seem to like any other parts put AcDelco. Has anyone used any other diaphrams and had success?
...WWhttp://www.tpis.com/parts/view/15
Melting Slicks
Joined: Dec 2009
Posts: 2,749
Likes: 50
From: Westmont Il.
The chain stores have the diaphrams for around +-$70.
Expensive for what I consider a weak link.
Don't forget the special tamper proof #10 torx bit you will need to remove the cover. Keep your old one in your emergency repair kit.
Expensive for what I consider a weak link.
Don't forget the special tamper proof #10 torx bit you will need to remove the cover. Keep your old one in your emergency repair kit.
Last edited by Joe B.; May 7, 2012 at 04:31 PM.
Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
If you can welld a little you can make your own. I did and used it for a while it worked fine. I did replace it later for a billet regulator.. just for looks tho.
All you have to do was drill a hole center of the cap and braze on a 1/4 20 nut, and then use a 1/4 20 bolt and jam nut screwed in it to adjust the spring pressure. You can use a penny or ball bearing on the inside to keep the screw from gouging the diaphragm.
All you have to do was drill a hole center of the cap and braze on a 1/4 20 nut, and then use a 1/4 20 bolt and jam nut screwed in it to adjust the spring pressure. You can use a penny or ball bearing on the inside to keep the screw from gouging the diaphragm.
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Safety Car
Joined: Jul 2008
Posts: 3,966
Likes: 4
From: Made In America
St. Jude Donor '10-'11
Im speaking from person experience. I have a very mildy modded L98 and bumped up to 24 lb from 22 lb Bosch III. I got a tune for it and a adjustable FPR from tpis along with the diaphram. Best damn money I spent. Get the adjustable or get nothing........
