Jump to content
The mkiv Supra Owners Club

12V Fuel pump mod


Guest Atomaton

Recommended Posts

Guest Atomaton

Hi guys,

 

Anyone know if the 12V fuel pump mod is a mandatory requirement or advisable when running de-cat with a restrictor ring?

 

Recently installed a walbro...

 

Was reading 0.7 bar before de-cat and now peaking at 1 bar.

 

Car seems to be running great apart from loss of traction!!

 

cheers

 

:)

Link to comment
Share on other sites

I wouldn't bother personally. Switch to 12v occurs as soon as positive boost is produced (on a J spec) so no real need.

 

Walbro draws less current so no need to replace factory wiring with dedicated feed for that reason, and it'll help preserve pump life (slightly) and reduce noise at idle too.

Link to comment
Share on other sites

I did an extensive search the other day, you have already done the right thing by fitting the Walbro.

 

The pump on the Uk car pumps more fuel than the J spec car, so only worth ugrading on the J spec.

 

The 12v mod doesn't apppear to be that popular or necessary.

Link to comment
Share on other sites

From the "Technical Bods" sticky thread at the top of this forum, by Ian C:

 

Name:

12v fuel pump mod

 

Also known as:

The fuel pump mod

 

What is it?

The stock fuel system of the Supra has a switched power fuel pump. Anything off-boost and it runs the pump at 9v. Anything on-boost and the ECU switches to running the pump at 12v. This is probably for pump longevity and maybe some NVH reasons. The 12v mod is where you wire the pump to always run at 12v in the belief this will improve your fuelling at high boost high revs.

 

Pros

A warm fuzzy feeling that you've improved your fuelling at high revs high boost for £0

 

Cons

It doesn't affect your fuelling one jot. At best, running the pump at a higher voltage when off boost merely shortens it's life a bit. It could also affect fuelling and drivability off-boost due to overpressurising the fuel system. As the pump switches to 12v as soon as you get on boost, this mod isn't going to change the behaviour of the fuel system when positive boost is occuring in the slightest.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.