I know its is recommended that when running higher boost that you should have a walbro fuel pump and rc 550's . With this said what will happen if these mods are not made? How much boost is safe to run without these mods?
Running more boost and fuel mods
- Thread starter 87 supra king
- Start date
some say 14psi, some say 18psi.. best way is to take it to the dyno, and gradually step up the boost with a afr probe in the exhaust rather than listen to someone on the internet who usually has no hard proof of what they're claiming or done any testing that they can yield results from. 
probbly only cost you $30-40USD, better than buying a new motor once you've smashed your ringlands, turned your bearings shards in the sump and put a gaping hole in your headgasket.
they're 440cc. you can do some calculations based on engine capacity and rpm to get you a ballpark figure, from there too many variables come into it so its best to dyno it. or wideband, take your pick.
probbly only cost you $30-40USD, better than buying a new motor once you've smashed your ringlands, turned your bearings shards in the sump and put a gaping hole in your headgasket.
they're 440cc. you can do some calculations based on engine capacity and rpm to get you a ballpark figure, from there too many variables come into it so its best to dyno it. or wideband, take your pick.
Last edited:
I have read that stock fuel pump is only 'reliable' to stock boost level.
I think 8-9psi can be run safely. Some have run more.
I run 8-9 normally with hi boost set on 12-13. I have also had rings destroyed.
I still have stock pump but won't be running higher than 8-9 till I get my mkiv pump installed.
I think 8-9psi can be run safely. Some have run more.
I run 8-9 normally with hi boost set on 12-13. I have also had rings destroyed.
I still have stock pump but won't be running higher than 8-9 till I get my mkiv pump installed.
isnms;1371359 said:
How many miles were on the car where the rings were derstroyed because I have a freshly rebuilt motor?
87 supra king;1371802 said:
So what you should be saying is - "I don't want to chance my freshly built motor with a stock pump".
For what its worth, i ran 12 pounds on a 7mge for quick some time with no problem. Stock injectors, stock afm, everything mostly stock interms of electronics and fuel.
I then blew the turbo.
7mge + 57 trim + 12 PSI on stock fuel and blew all the rings.
Happy boosting
I then blew the turbo.
7mge + 57 trim + 12 PSI on stock fuel and blew all the rings.
Happy boosting
One of the cheapest mods you will ever do is the Walbro pump. When I bought mine from Driftmotion, I think it was $98. Yes, you do have to drop the tank to install it. I myself was so scared of doing that, until I did it. But, when I did it, I brought along my camera and snapped pictures of every bolt and wire you touch. When finished, I posted an article in the articles section of both the Walbro install and the 12 Volt Mod. If it weren't for the jacking and securing the car, I could do the install in less than an hour by myself. If you have a helpful friend and a floor jack, it would be very simple. There is one fuel line to break loose with tools. There's 2 more rubber hoses with pinch clamps you can take loose with your fingers. Then you have 4 screws at the gas cap, and 2 metal straps to take loose. It's just that simple!
Doing the pump itself is a 5 minute procedure, and very easy.
I just pulled the tank I did the article on from that car, and transferred the whole tank to a different car yesterday. Another simple job that I did in my driveway by myself. Trust me, I am no mechanic. You CAN do it!
Now, once that is out of the way, you can worry about injectors a little later. Your 440's are good up to at least 350HP or more. If all you want is 12PSI, they will be safe for a while. Your stock fuel pressure regulator is a 1:1 rising rate regulator. You don't need to worry about that yet either. If you decide to upgrade your turbo, you can worry about all of those other upgrades you always hear about. But, do these mods before upgrading the turbo.
Doing the pump itself is a 5 minute procedure, and very easy.
I just pulled the tank I did the article on from that car, and transferred the whole tank to a different car yesterday. Another simple job that I did in my driveway by myself. Trust me, I am no mechanic. You CAN do it!
Now, once that is out of the way, you can worry about injectors a little later. Your 440's are good up to at least 350HP or more. If all you want is 12PSI, they will be safe for a while. Your stock fuel pressure regulator is a 1:1 rising rate regulator. You don't need to worry about that yet either. If you decide to upgrade your turbo, you can worry about all of those other upgrades you always hear about. But, do these mods before upgrading the turbo.
now please correct me if im wrong but there is a hatch in the boot you remove to get direct access to the fuel pump...?
i've never removed the pump but i have popped the cap off to take a squiz.
i've never removed the pump but i have popped the cap off to take a squiz.
paradox616;1373477 said:
no.... if you are real close to empty.. drop tank.. if not.. cut a hole if you want.. lot do...
remmber higher boost... + run lean == short life
What is it now? I'm averaging 17mpg in the city. Epa when new was 18mpg city. I'm using RC550's and a MKIV Denso fp. Ymmv. gl.
If you Dont change injectors or fuel pump turn the boost up untill you hit fuel cut. It will cut before you have a chance to do any damage unless you slap on a piggy back and pull tons of fuel.
These mods are more then they seem, yes you need bigger injectors and bigger fuel pump to support more boost but you also need them to be able to turn the boost up in the first place with the stock TCCS.
Without changing injectors you cant fool the computer into raising fuel cut unless like i said you slap on a piggy back and pull tons of fuel. so barring something obviously stupid as pulling tons of fuel with a piggy back on stock injectors with out a wideband your limited to 9-12psi stock fuel cut.
These mods are more then they seem, yes you need bigger injectors and bigger fuel pump to support more boost but you also need them to be able to turn the boost up in the first place with the stock TCCS.
Without changing injectors you cant fool the computer into raising fuel cut unless like i said you slap on a piggy back and pull tons of fuel. so barring something obviously stupid as pulling tons of fuel with a piggy back on stock injectors with out a wideband your limited to 9-12psi stock fuel cut.