Engine/Transmission (1994 - 1998) Custom Fuel Plate / Boost Elbow

[RIT]

I have a 1997 12V Auto with 190,000 miles that I recently got enough courage to start bombing. I broke into the 7100 this weekend to examine the fuel plate and try my hand out at grinding some power out of it. I guess it is somewhere between a #8 and a #10. I am unable to post a picture of it since it is still in my cell phone. I managed to get some power out of the modification and a good deal of smoke. The AFC housing is set full forward, fuel plate is in the stock position, and I cranked down the star wheel to kill about half of the smoke. I learned quite a bit in the process and have a couple of questions.



1. My AFC housing has a rubber hose connected to a port on the intake. One connection only. If I manage to find someone that will sell me just a boost elbow how to I connect it?



2. Where can I buy just a boost elbow?



3. I now have to use a little pedal in the morning or after my truck sits for 4-5 hours. I plan to put new banjo bolt gaskets next time I go to the dealer. Is there anything else that i am missing that could cause this bleed down of fuel pressure?



Thanks,

 

[PRohr]

You can get boost elbows off eBay or you can make your own... ot's just a brass 1/8" NPT elbow with a small set screw to choke off flow.

 

[Joe G.]

3. I now have to use a little pedal in the morning or after my truck sits for 4-5 hours. I plan to put new banjo bolt gaskets next time I go to the dealer. Is there anything else that i am missing that could cause this bleed down of fuel pressure?

Having to use a little pedal to start it is no problem. This things don't have a computer to take care of the starting requirements so sometimes you have to help a little. Setting the idle up will make it start better with no pedal. I like mine to idle a little bit lower and always use some pedal to start it. Saves wear on the starter too.



How to you know that you have a bleed down of fuel pressure? Do you have a fuel pressure gauge on it?



Email me at -- email address removed -- for my 12 valve fuel supply system write up, how it works and how to fix it.



As far as the boost elbow is concerned you can install a needle valve to do the same thing.

 

[champspa]

buy one from tstproducts.com it's already set so you will make about 28-32 lbs boost.

 

[RIT]

I just ordered a boost elbow off of ebay. It looks like it will connect directly into my turbo. I do not have a fuel pressure gauge installed. I just thought that i may be getting a little bleed down since I have to use pedal only when the truck has been sitting for a few hours and is cold. Once I start the old bomb, I can shut it down and restart without pedal. I guess I need to put a fuel pressure gauge on it and stop pulling shadetree diagnostics. I already have Joe G's writeup. It has been quite helpful for troubleshooting my fuel system in the past. Thanks Joe... ...

 

[Missouri Mule]

Do you have your boost and Exhaust temp quages already set up?

 

[RIT]

Naw Mule... hehehe ... no gauges yet. I ordered some a few days ago. They should be in tomorrow. I have not pushed the old bomb too hard yet. No towing and very limited pedal pushing over 2200 RPM. I think that I am safe until I get them installed. I plan to wait to install the boost elbow until after the gauges. Thanks for your concern.

 

[champspa]

the boost elbows I've seen from ebay are restrictors not bleeds can't see how the restrictor ( really small hole no bleed ) will work as far as fooling the waste gate. the bleed keeps the waste gate from dumping as quickly . at least that's the way I perceive it . Some of you Diesel heads jump in here.

 

[RIT]

Whoops...



I woke up this morning to the recent starting issues caused by my plate grinding experiment. I took a good look in the area where I was working and found that the fuel line that attaches between the 7100 and the fuel filter canister was loose on the fuel filter canister side. I guess when I moved the fuel line to access the the afc housing screws, I pulled on the fuel line enough to loosen the fuel line connection to the top of the fuel filter canister.



The boost elbow that I ordered is drilled and tapped for an allen head screw for restriction. It is my understanding that the screw can be tightened for higher boost levels or loosened for lower boost levels. It restricts the amount of air that is sent to the wastegate and therefore changes the time at which the wastegate opens. If I am wrong, please correct my understanding of the boost elbow before I blow something up.



Thanks

 

[champspa]

I believe you have the correct elbow, never seen one like that on ebay.

 

[RIT]

It would be interesting to see any pictures y'all have of "home ground" fuel plates. I am sure that there are quite a few different profiles out there. I will get the ball rolling on this one. Here is my latest grind. Does anyone have any constructive criticism on my profile selection.



Thanks

 

[Dieseldemon]

Bleed or restrictor it is the same they slow down the boost to slow the opening of the waste gate but if you got one from E-bay make sure it has a bleed hole on the other side of the restrictor so when you get off of the throttle it dumps the pressure and lets the wastegate close.

 

[RIT]

Bleed or restrictor it is the same they slow down the boost to slow the opening of the waste gate but if you got one from E-bay make sure it has a bleed hole on the other side of the restrictor so when you get off of the throttle it dumps the pressure and lets the wastegate close.

Thanks for the heads up Dieseldemon. I was not aware that you needed a bleed hole on the on the restriction type of boost elbow. My boost elbow came in the mail today and I checked to make sure that it had a bleed hole. It is an extremely small hole but it will bleed off pressure pretty quickly I guess. I am posting a picture of the boost elbow to that others can see what is going on.





Thanks again,