Bags

iTrader: (3)

Ok, so my dyno guy keeps telling me to trash the FMU and get bigger injectors and a rising FPR.

I am trying to do this right the first time... without spending $20 here or $50 there then end up spending $500 and getting it right.

I see so many people on this board running fmu's and stock FPR's and having good results. BUT that seems to be with an SAFC.

And maybe I need to bite that bullet and get one. I just do not have the money for a SAFC , new tires, and new brakes.

So I am asking to see if I can have good success with just an FMU or an FMU and a aftermarket FPR?

And good success is anything over 11:1 A/F while under 13:1

Thanks

sx7r

iTrader: (15)

i currently have AEM FPR, Cartech FMU, S-AFCII.

When i first went in to tune, with the FPR, FMU, and Fields SFC, i was running so rich between 2k and 4.5k, that it wasn't even on the graph. after 5k it'd start to lean out a bit. When we started adjusting the Fields SFC, we were able to bring it to 11.5:1 across the range with no problem.

Bags

iTrader: (3)

Thanks sx7r, I guess the cartech fmu is the way to go, adjustable, and the SAFC I or II.

Just sucks , but I found one for cheap today so I may bite the bullet and sell more plasma.

Stephen Max

iTrader: (59)

Thomas, if you don't mind me asking, why are you using the AEM fpr instead of a Sard? I was just about to order a Sard from you until I saw this.

sx7r

iTrader: (15)

I bought the AEM before I started selling SARDs. However, since SARD USA no longer exists, I'm not selling SARDs anymore. Now I sell the AEM FPRs. The AEM is more expensive, but you get a couple more features. There are two ports on the pressurized side in addition to a standard 1/8NPT gauge port. Also, you can change the size of the discharge port to match the flow of your fuel pump. This is especially helpful for those running high fuel pressures, as it takes care of the hanging of fuel pressure after WOT.

Stephen Max

iTrader: (59)

What's your price? Also, I understand the AEM is adjustable down to 20 psi, is that correct?

Thanks!

BigDogJonx

iTrader: (7)

Im a bit thick here, help me out.

Whats the FPR for if you got the FMU? I got a cartech fmu and the SafcII to fine tune. But what is this FPR then you all are talking about? Is that to replace the stock FPR to control the idle fuel pressure and all?

Dixit

Stephen Max

iTrader: (59)

In the Stillen SC kit, you are supplied a boost referenced fmu that controls fuel pressure during boosting to supply extra fuel. The fuel pressure during normal (non-boosted) operation is still controlled by the OEM fpr. In my case, I would like to go to an adjustable fpr for two reasons:

1) I'm using the Walbro 255 lph fuel pump instead of the aux fuel pump that comes with the kit. The Walbro fuel pump raises the base fuel pressure by about 8 psi, so if you want to go back to the stock base fuel pressure you need an adjustable fpr. This is not really critical, though.

2) The real reason I need an adjustable fpr is because I intend to install 370 cc/min injectors in the near future, and to do so without also paying the $$ for the ECU upgrade, I need to adjust the fuel pressure downward to a point where the oem ECU can handle the extra fuel during closed loop operation. Matt has shown that this is possible to do. I will use an SAFCII along with the boost referenced fmu for tuning boosted operation.

sx7r

iTrader: (15)

AEM does go down to 20psi.

96BLUMAX

iTrader: (3)

How do i know if my FPR is a rising one? I have a weapon-r one.

ejj

iTrader: (5)

Does the SARD?

BigDogJonx

iTrader: (7)

This is the info I wanted. Good stuff. I knew there had to be someway of bringing down the fp from having the walbro installed.

Now for my ride, since they dont make larger injectors as of yet, would getting an aftermarket FPR be needed? or should I just live with the extra 6-8psi more that walbro is giving me at idle?

Dixit

sx7r

iTrader: (15)

yes, SARD also goes to 20psi.

Redmax

iTrader: (20)

yeah, sx7 how much are you selling the aem for?

ok but now Stephen Confused me. Im a little dense when it comes to this stuff. Is he saying that if you have the vortech FMU which is a boost referenced fmu then, you dont have to use a fpr? Now also are you guys saying that if you have an adjustable fpr that you will not get the bogging down that you may get sometimes after you have run the car at wide open throttle and then stopped lets say at a light. My car sometimes seemed as if it were going to idle erradicly or was going to shut off.

Stephen Max

iTrader: (59)

If you are using a vortech fmu you also have to have either the OEM fpr or an aftermarket adjustable fpr. The fmu only controls fuel pressure when there is positive manifold pressure (i.e. boosting). At all other times the fuel pressure is controlled by the OEM fpr (or an adjustable fpr if you have one).

One reason people are replacing the oem fpr with an adjustable fpr is because the Walbro fuel pump raises fuel pressure by about 7-8 psi. With an adjustable fpr you can lower the base fuel pressure back to stock levels. Also, Matt was able to successfully run 370's without having his ecu reprogrammed by lowering the base fuel pressure with an adjustable fpr.

Why you get bogging at idle I can't say. Could be a IAC problem, throttle body needs cleaning, lack of a recirculating bov loop, where you have your maf located, etc.

DA-MAX

iTrader: (10)

that was my guess....at the meet last month Coreys car was sptting straight black soot out of the pipes(ie-rich) and the bogging is a sure sign as well. to this day I've never seen a MAF car run well with open atmosphere BOV. the only option I'd say is to tune it/use a VPC(if you can find one), but even with that its not worth it or nearly as easy as running recirc...which I bet is the cause of his probs

guestNX

or put the MAF after the BOV on a 4th gen.. problem solved, and you'd see a MAF car run perfect w/ an open atmosphere BOV.

i like the 370 injectors without an ecu idea.. good info on the FP and safc - thanks

DA-MAX

iTrader: (10)

only way to do that is put the maf on the charge side and I thought that was the whole problem to begin with on the 4th gen kits...pressurized air through the MAF wasn't cutting it and casuing probs. I don't really think there is any way around it!

guestNX

hm exactly who is having problems with pressurized maf's on 4th gens. if i recall correctly, stillens 4th gen supercharge kits pressurized the maf (i am unsure of what year they switched to nonpressurized, but whenever the 5th gen mafs started on maximas)

guestNX

rising fpr being a fmu..? i dont understand what he is telling you to do.. but yes bigger injectors would be good, just remember what goes with them - more tuning.

does anyone have any knowledge or experience of the HKS AFR other than just what is on their website? seems like a very good unit, and at a cost of only ~$200 (list approx 279 i believe)

bags you could get an old SAFC unit for under 100 bucks too (not the digital screen SAFC I's)... but only offers +/- 20%

DA-MAX

iTrader: (10)

if I recall some of the turbo guys when they first started these kits had problems with MAF on the charge side...I'm a little foggy about it, cause I didn't really used to pay attention to the whole turbo 4th gen thing

as for the AFR, check the Supra boards(I browse the MKIII section occasionally)...many of them are using the AFR since it somewhat has that "automatic" EIDS function for BOVs. check the Supra boards thats where I've seen it used most, but even with the EIDS some still had probs with open atmosphere.

Jeff92se

iTrader: (82)

You know instead of hassling with all new injectors, why not run a 7th and 8th injector and a seperate fuel ecu to control those? That way you have decent idle and part throttle running and extra fuel when you need it. Trouble is you have to mount them somewhere less than ideal for fuel atomization. ie.. near the TB or something.

Redmax

iTrader: (20)

Once you start using alot of boost u cant put the maf on the charge side. the mafe will get destroyed from the volume of air

guestNX

proof of this, and at what psi are you talking about? I know at 15-18psi the stock 4g maf is perfectly fine.



no, you have it backwards.. they had issues when they put the MAF on the non-charge side, getting idle, boost->noboost transitions, etc because partially yes - of the atmosphere BOV. now, getting back to my point, MAF on the charged side, it runs 100% perfect.

and the supra guys? reason they will experience trouble is they have it on the non-charged side, and of course that brings us to the same problem all over again with BOV. I don't know why we got spoiled by nissan with strong 4g MAFs that can be pressurized, but who is going to complain about that.

ereet

At 15psi, you're pushing over 350fwp. The stock MAF can't read more than that, so at 18psi, you're definately going to need a better MAF or an emanage to be able to process that amount of air. I'm not saying you'll "destroy" your MAF by running 15-18psi, I'm just saying your ECU won't be able to read that much air.

Stephen Max

iTrader: (59)

If you're using a boost referenced fmu then it doesn't matter how much air you're pumping through the maf.

ereet

Harumph. I suppose you're correct. The MAF won't know what the heck is going on, and neither will the fuel system, however because neither depends on the other anymore with the FMU, that'll work. Woops

MardiGrasMax

iTrader: (14)

FWIW, Vortech Super FMU has the abality to adjust base fuel pressure so no FPR is needed.

IceY2K1

iTrader: (3)

I would go for the adjustable FPR or Vortech Super FMU to correct the base idle fuel pressure. At least two reasons:

1)During startup/warmup your ECU goes open loop. If your base fuel pressure is 6-8psi higher while you're in open loop, your ECU is not going to be measuring 02's and you'll be running rich. Depending on how rich, you can foul plugs, soot 02's, and even ruin a cat.

2)Once the car has warmed up and is in closed loop, you're going to be rich and your ECU will decrease injector pulse width to compensate, ie lean you out. This MAY be fine, however there has to be a limit where the injectors don't open far enough to properly distribute/atomize fuel or you still run rich.

I know there is more, but I can't remember right now.

IceY2K1

iTrader: (3)

Agree...been saying that for a long time. I've seen a universal HKS aux injector controller, but I'm not sure how good it works.

Stillen is using this method on their SC, but they designed a whole new plenium for the SC+7th injector.

I think the atomization problem will be a concern, but if guys are running wet N20?

turbo97SE

iTrader: (3)

I agree with this. Some of the japanese tuners add additional injectors rather than messing with larger injectors. You can keep your stock fuel maps and throw in additional fuel when needed. The emanage has this capability built in for 2 additional injectors. For 2002+, unless you go through the pain of running a return line, this is probably the best way to go!