Tuning in fuel pressure

[hemi8]

Took the GN out for its maiden test drive with razor's alky kit this morning and all I can say is you cannot wipe off the smile from my face. I am right at 20 psi, no knock on Casper's gauge but from my O2 gauge and the EGT gauge I am running lean. I was seeing 670 O2 and over 1600 egt, I pulled out of it and pulled over and bumped the pressure up to 46 psi up from 44 psi. This brought the o2's to 710, I still see no knock, the egt's came down below 1600. Question is this, at what point do I stop increasing the fuel pressure and start adding fuel via the TurboTweak 93 Alky chip? I run 50 lb injectors, Red's twin fuel pumps, (hot wired).
Mike
86 GN

 

[pacecarta]

dont bump pressure using regulator unless your blms are over 128 at idle
adjust fuel pressure so your idle blms are close to 128
if fuel is needed for WOT add it in the chip or dial in more alky or run less boost

there is a sticky at the top of this forum for tuning with the kit

what is your combo , with twins your fueling should be way rich unless there is a restriction
, make sure the regulator is increasing with boost

best is to get a wideband on it and tune from there

 

[Razor]

Took the GN out for its maiden test drive with razor's alky kit this morning and all I can say is you cannot wipe off the smile from my face. I am right at 20 psi, no knock on Casper's gauge but from my O2 gauge and the EGT gauge I am running lean. I was seeing 670 O2 and over 1600 egt, I pulled out of it and pulled over and bumped the pressure up to 46 psi up from 44 psi. This brought the o2's to 710, I still see no knock, the egt's came down below 1600. Question is this, at what point do I stop increasing the fuel pressure and start adding fuel via the TurboTweak 93 Alky chip? I run 50 lb injectors, Red's twin fuel pumps, (hot wired).
Mike
86 GN

Your leaning out hard. You need more fuel using injector duty cycle. But first make sure your fuel pressure goes up 1PSI per lb of boost. Maybe your fuel pressure reg is not happening???

The fuel on the 93 and alky chip is the same. Timing is higher on the alky chip. So getting an alky chip wont make it run any richer. Definately look at your fuel pressure not dropping.

HTH

Julio

 

[hemi8]

Hooked the fuel pressure gauge up to it this week and took it out this morning before the town woke-up and made some power runs. Fuel pressure is rock steady @20lbs higher than @ idle. Base fuel pressure is at 46psi, O2 was even lower today, 660 WOT, probably due to cold 19 degree air, EGTs were climbing for 1600. Casper's knock gauge barely lit the 1st light.
Should I add fuel via the TurboTweak Alcohol Chip or are my injectors too small? The car is making soo much horsepower it will spin the tires @70mph if I nail it.
Combo: PT&E highly ported GN1 aluminum heads.
Newly designed Champion intake, 70mm TB
50lb injectors, Red's twin pumps, hot-wired.
ATR flat tappet cam 205/215
ATR headers, JE pistons, steel caps, ARP etc.
TE63 PT&E turbo, 3" DP
CAS Frontmount
Razor's Kit

 

[pacecarta]

fuel needs to be 1-1 off static fp (line of FP regulator), not idle
so with base of 46psif FP and 20psi boost did you see 66psi FP?

and cold air can lean a motor out since you really have no method in the ecu of correcting fuel for the dense air at WOT unless you have a wideband correcting system , with stock ecu and chip setup you need to adjust fueling when temps drop .

 

[hemi8]

Thank you for the reply, I saw 60 lbs of pressure, its about 40 with the vacuum line on. So what should I look for to correct problem? Could the regulator not be seeing the correct boost pressure?
Mike

 

[yullose]

I would definitely add fuel via the chip...for the colder weather.

Example...

About a week ago, I took my GN for a ride.
It was exactly 30 degrees outside. The car was at "chip specs" and untouched. 43psi fuel pressure.

I made a WOT blast and saw.... 670 on the scanmaster.

I pulled over, got the Turbotweak instruction booklet out of my console... read it, and added 15% add'l fuel.
Went back out on the road and mashed the pedal...

O2's were right up where they belong... 800 to 8-teens.
Never touched the fuel pressure regulator.

Now... when it warms up again, all I gotta do is put the chip back to original out-of-the-box specs and I'm good to go.

Thank you for the reply, I saw 60 lbs of pressure, its about 40 with the vacuum line on. So what should I look for to correct problem? Could the regulator not be seeing the correct boost pressure?
Mike

Pull the vacuum line off... set fuel pressure to 43psi and start from scratch. Let the chip handle the fueling.

 

[hemi8]

Plumbed into a different line for boost/vacuum and it came up to 65/66. Same problem with 02, starts at 720 and drops as mph goes to 80-90 so I'll add in fuel via the chip and see what happens.
Mike

 

[Razor]

I'll tell ya this. Playing with a car that is leaning out is like putting your hands in a wicker basket full of snakes. You need to immediately drop the boost a lot and get the O2's up.

You start very very very rich and work your way lean. Playing with a car that can be lean is very $$$$$ costly. I dont know how else to put it to ya.

If you pull the vacuum line off.. that IS your base fuel pressure. On the TT chip its starts at 43 PSI line off. Hopefully your guage is accurate. Then at 20 PSI your fuel pressure HAS TO READ 63 PSI. Any less.. you have problems/will have problems. Get this part..

Then we can work on adding fuel via CHIP programming if it still reads low.

I would drop boost to 18 PSI on your motor, add all 10% fuel on the chip.. and start rich blowing black smoke. Then work on leaning it out.

43+18=61 PSI fuel pressure.

Not to say you dont have a bad O2 sensor.. but work on getting the O2's into the 800's. Should not see 700 anything until 120 MPH.

 

[Hognose]

I'll tell ya this. Playing with a car that is leaning out is like putting your hands in a wicker basket full of snakes. .

Whats wrong with that!!:biggrin:

I am just curious, what is the duty cycle of your injectors? It looks as though you have a heck of a setup! I would think that you might be at the limit of the 50's. I am just throwing out the suggestion. Do you have Direct Scan?

Also where in Herndon are you trying your car out! LOL I used to live in Sterling, so I know the area. Be carefull! You have some guts,with these cold roads I haven't really tried tuning much because of traction.

Good luck, Nice looking motor!

Matthew

 

[hemi8]

Yes, the fuel pressure is good, for some reason the pressure coming out of the normal FP line is not the same as where I have my boost gauge piped-in. It's about 4psi lower so I switched it and FP is good. It looks like the TT chip has an adjustability of up to 20% at WOT so I will bump it up to this and see if we go super rich and come back from there. This will have to wait till next week, snow storm coming.
Mike

 

[TurboBuRick]

Like the guys said, use FP to tune BLM to 128-132 while cruising.
Use the chip or translator to add fuel to WOT.

Nice motor

 

[pacecarta]

Yes, the fuel pressure is good, for some reason the pressure coming out of the normal FP line is not the same as where I have my boost gauge piped-in. It's about 4psi lower so I switched it and FP is good. It looks like the TT chip has an adjustability of up to 20% at WOT so I will bump it up to this and see if we go super rich and come back from there. This will have to wait till next week, snow storm coming.
Mike

the chip will allow 20% but you can only get 100% from an injector ,
if your injectors are only seeing 80% at peak demand then you can adjust 20% , but if they are at 90% already you can only add 10%
you need to log your pass and see where the injectors are
in calcs the 50s should be able to support your combo with alky but doesnt leave much room for safety . personally i would run a bigger injector , get flare and get a boost spike and the alky will kick in some to cover but its still dangerous with injectors pushed that close their limit

 

[hemi8]

What is the biggest injector that I could run with my set-up? I agree with you that it must be better to run a bigger injector at a lower duty cycle than to ram a small injector to it's limit. I mean at some point you have to punt it and switch to DFI but I do not want to do that. Also, looking at the Innovative WB, it looks like I could lose half my gauges if I use a WB to tune it to 11.5, sure looks like it would simplify things.
Mike

 

[JoeNational]

You should bump them up to 60#ers. Right now that is the largest injector you can run without having to mod the ECM. I would also make sure your pumps are working properly as well. I have had two XP pumps fail on me. With the new injectors I will be throwing in a Walbro 340m (think this is the newest pump by them) I am currently running my injectors to about 92% duty cycle . I do not want to push it anymore or something bad will happen and I will be watching everybody race instead of doing it myself. I run 42.5#er's and have been running rich througout the whole run thankfully. I would make sure your regulator is running good too.

 

[2QUIK6]

With 50# injectors and boost being 25# or under and running alky, there's no way you're out of injector with a TE63.
With a TE61 and 27# of boost, my 60#ers run at around 60-65% DC.