Jump to content
TxCMC22

4.6 numbers?

Recommended Posts

Glenn
Just throwing out ideas here, but it seems like the only way to adjust fuel pressure in a returnless system at wide open throttle is to increase fuel pump output. A larger fuel pump with an adjustable voltage regulator seems like a possibility. If I remember correctly, there was a supercharger installer, possibly Kenne Bell, that made a "Boost-a-Pump" module that bumped up pump voltage under high demand situations.

 

Found it - http://www.kennebell.net/accessories/boostapump/boostapump.htm

 

Numerous comments made to me about the legality of this. I'm sure you guys know its not legal - right?

Share this post


Link to post
Share on other sites
sacabuche

I did some research and found there is really no fix for the lean fuel ratio. Unless there is an actual problem that restricts the extra fuel needed, i.e. restricted fuel filter, weak fuel pump, or a biased sensor.

 

The ECU actually adjusts the voltage to the pump to decrease or increase fuel pump output, with the help from the fuel rail pressure sensor, MAF, and O2 sensors and determines what is actually needed.

 

So, if everything is operating as designed, I would switch to the first gen fuel system that is stock on the 96-99 mustangs with a mechanical fuel pressure regulator that can be adjusted manually.

Share this post


Link to post
Share on other sites
TxCMC22
So, if everything is operating as designed, I would switch to the first gen fuel system that is stock on the 96-99 mustangs with a mechanical fuel pressure regulator that can be adjusted manually.

 

 

Good thought, but the computer controls this, so even with a regulator system, wouldn't I still be in the same boat? unless I changed computers, ignition system, wiring harness, etc? I run coil over ignition, I would need magnetos, and everything to go along with it.

Share this post


Link to post
Share on other sites
nasa-rm
So, if everything is operating as designed, I would switch to the first gen fuel system that is stock on the 96-99 mustangs with a mechanical fuel pressure regulator that can be adjusted manually.

 

 

Good thought, but the computer controls this, so even with a regulator system, wouldn't I still be in the same boat? unless I changed computers, ignition system, wiring harness, etc? I run coil over ignition, I would need magnetos, and everything to go along with it.

 

Jeremy, I have a hybrid. Let's talk at Hallett as I have ideas for you.

Share this post


Link to post
Share on other sites
TxCMC22
So, if everything is operating as designed, I would switch to the first gen fuel system that is stock on the 96-99 mustangs with a mechanical fuel pressure regulator that can be adjusted manually.

 

 

Good thought, but the computer controls this, so even with a regulator system, wouldn't I still be in the same boat? unless I changed computers, ignition system, wiring harness, etc? I run coil over ignition, I would need magnetos, and everything to go along with it.

 

Jeremy, I have a hybrid. Let's talk at Hallett as I have ideas for you.

 

Cool, Look forward to it. Can they be discussed here for everyone? and for people searching in the future?

Share this post


Link to post
Share on other sites
TxCMC22

4.6L owners, it's that time of year. I am in the process of getting a rules change proposal together, to use the steeda timing adjuster to get to power. I have purchased the unit without knowing if we will be able to legally use it. I am gathering data and going to put my car on the dyno for a half day to get some hard data results. I still need your help though. I am trying to get a few of the dyno's in PDF form, or scanned in .jpg to use as comparisons. If you would be willing to shoot me this information to help our case, Please forward this and a list of your mods to [email protected]. Put "timing adjuster" as the subject so I can sort the e-mails and attach to the proposal.

 

I have read a lot on this modification, and it is a good alternative for the series, cheap, police-able, easy install, available, and should "in theory" bring our motors to the limit of the rule set. I know this is a pain in the butt for you, and we are all busy, but if you could take some time to help me state our case I would appreciate it. Also, any help, advice, comments, thoughts whatever are more than welcome. I plan on submitting in the next couple of weeks, so if able, jump on board and lets try to make this happen.

 

Thanks in advance!

Share this post


Link to post
Share on other sites
Glenn

Jeremy spoke w/ Al and myself this weekend about this. If any of you are making the number w/ the motor in question, please get w/ a series director and relay this info to us as well to Jeremy.

Also, be a "good citizen" of the series and please help him w/ this proposal.

Share this post


Link to post
Share on other sites
TxCMC22

UPDATE:

 

I spent about 5 hours on the Dyno Sunday, without any conclusive evidence. but the search is not over. I believe I have found an issue with my air/fuel ratio. Although I haven't been able to pull codes (out of town this week) I will pull them as soon as I get home. I usually run 12.7 -13 AF ratio, I was running 14-14.7 all day on the Dyno. The consistency was not there due to the computers reaction to all of this (my opinion) We shall see what happens when I get this fixed. I will keep the updates coming... Please feel free to chime in with any ideas or information. There is a lot of manpower in Texas going into this, and we would love to have your opinions and experience on this.

Share this post


Link to post
Share on other sites
nasa-rm

Have we determined if 99- 4.6's can LEGALLY scrap the returnless system and convert to the setup used in the 96-98? Then a regulator could be used.

Share this post


Link to post
Share on other sites
Al F.

Yes, you can backdate to a return fuel system and then use an adjustable regulator.

Share this post


Link to post
Share on other sites
nasa-rm
Yes, you can backdate to a return fuel system and then use an adjustable regulator.

 

Jeremy,

 

Go get a fuel pump and rail from a 98. The pump will drop into your existing tank.

 

Run the pump straight off the pump relay and delete everything that has to do with the variable voltage.

 

Add an extra return line back to the pump and you should be good.

 

Not sure what the ECU will do with this, but it's worth a shot.

Share this post


Link to post
Share on other sites
TxCMC22

That's a good idea, I might try that if all of this doesn't work. I have a feeling the computer is going to flip out though. Personally I don't want to start swapping to much stuff that comes stock from the factory, it does nothing but cause problems with reliability, which is one of my goals with everything I do to my car.

Share this post


Link to post
Share on other sites
NickS
13:1 on a dyno is lean.

I didnt ask about the red line of the motor, but rather the rev limiter. Where does the computer limit max RPMS. Why does it matter you ask? If you can mechanically spin the motor 1K RPMs more than me, you have an advantage. I dont think thats the case, but I wanted to know cause it matters.

 

 

Eric, the site will not allow you to attach the dynojet files. our own AICMCTexas site will not allow it either. I have several files. I wish we could post them. Care to send me what you have? I'll send what I got also.

 

 

Send them to me. I'll put them up on server and post a link to this thread.

 

Snicko (At) Noid (dot) org

Share this post


Link to post
Share on other sites
GT4Point6
Yes, you can backdate to a return fuel system and then use an adjustable regulator.

 

Jeremy,

 

Go get a fuel pump and rail from a 98. The pump will drop into your existing tank.

 

Run the pump straight off the pump relay and delete everything that has to do with the variable voltage.

 

Add an extra return line back to the pump and you should be good.

 

Not sure what the ECU will do with this, but it's worth a shot.

 

Search the net on this, there were a lot of returnless guys who put on superchargers that converted to the return system. If I remember right, it took computer mods to work properly which isn't legal in CMC.

 

One of the problems I believe is that the ECU is looking for variable pressures at the rail (rail pressure sensor is on drivers side rail) as it varies the fuel pump voltage.

 

I don't remember my fp numbers but it was different at idle than it was under load. Not a consistant xx PSI like most return systems.

Share this post


Link to post
Share on other sites
GT4Point6

On the note about running the exhaust out the rear, I did and the numbers for tq and hp numbers/curve were identical to just having dumps. It does adds some weight if your looking for legal ballast but may have clearance issues if you run a panhard bar. Makes the car MUCH quieter inside for sure, that is the biggest benifit.

 

Jegs has a cheap cat-back in 2.5, nothing smaller. Just dump the muffs and put a pipe in its place. Sounds good too.

Share this post


Link to post
Share on other sites
TurboShortBus
Search the net on this, there were a lot of returnless guys who put on superchargers that converted to the return system. If I remember right, it took computer mods to work properly which isn't legal in CMC.

 

One of the problems I believe is that the ECU is looking for variable pressures at the rail (rail pressure sensor is on drivers side rail) as it varies the fuel pump voltage.

 

I don't remember my fp numbers but it was different at idle than it was under load. Not a consistant xx PSI like most return systems.

I have seen this change made with the Superchips or SCT software (I can't remember which) at my buddy's shop. It is literally a matter of clicking an option box for "constant speed fuel pump," or something to that effect, then downloading that new program into the EEC. Of course, that is illegal per CMC rules.

 

I can't say what the EEC will or will not do if you if you hot-wire the pump to run at a constant speed and install a return line, but I can look into it. I would expect that the EEC will be looking for a desired set of results as it attempts to vary the fuel pressure, but if it doesn't see those results, it may resort to other methods which may or may not be desired.

 

Even return-style fuel systems have different fuel pressures at idle and under load. On my Fox 5.0L, fuel pressure was 38 psi at idle and 42 psi at WOT (or idle with vacuum hose off). On my SN95 5.0L, fuel pressure was 36 psi at idle and 44 psi at WOT (or idle with vacuum hose off).

 

Mark

Share this post


Link to post
Share on other sites
JermBua

When are we going to see some dyno results

Share this post


Link to post
Share on other sites
Glenn

I know Jeremy Gunter was planning a dyno this week.

Share this post


Link to post
Share on other sites
JermBua

Sweet

Share this post


Link to post
Share on other sites
CMC#11

I'll let Jeremy chime in with the details but we dyno'd today and he got 258/299.

Share this post


Link to post
Share on other sites
JermBua

Good numbers. Thats exactly my peak number too. I wonder what the low torque curve is. Hopefuly better than my push rod engine. Those LS1s are killing us ford guys on the low end torque.

Share this post


Link to post
Share on other sites
CMC#11

His low tq curve is sweet.

My 5.0 did 261/295 and our tq curves from 4k up look identical but his is much higher from 2-4k.

Share this post


Link to post
Share on other sites
TurboShortBus

Is it possible to post a link to the dyno sheet, and/or post a list of specific modifications (not that many are allowed) that were used to get to those numbers? Unless the information is proprietary, of course. What was done about the fuel system?

 

Mark

Share this post


Link to post
Share on other sites
Waco Racer
His low tq curve is sweet.

My 5.0 did 261/295 and our tq curves from 4k up look identical but his is much higher from 2-4k.

 

He must be cheating.

Share this post


Link to post
Share on other sites
Glenn
Is it possible to post a link to the dyno sheet, and/or post a list of specific modifications (not that many are allowed) that were used to get to those numbers? Unless the information is proprietary, of course. What was done about the fuel system?

 

Mark

 

We don't want to talk much about what he has done yet. It is a work in progress.

What we do need is more 4.6 dyno data and AFR data to support the approval of this "fix".

Share this post


Link to post
Share on other sites

×
×
  • Create New...