Feels like my SR is leaning out...

[wizdom98117]

Recently I've noticed my motor not boosting as hard as it did before. It feels a lot more boggy now.
i) When I am in a low gear at low rpm (ie: 2 gear, 2500 rpm) the motor has a slight stutter, almost like it's not getting enough ignition, I know the turbo is okay because you can hear suction from the intake as well as the BOV setting off. I changed out the fuel filter, so I know that's not the problem.
ii) When I'm in high gear at high rpm (5th gear, 6000 rpm), when I reach 115 mph (sometimes lower mph), the fuel cuts off immediately. If i'm not mistaken, these motors come w/an ecu to handle up to 120-130 mph, is that correct?? If so, why does it cut off so early?

This may not be the exact cause for it but it may help you get an idea, it seems as though the boggyness happened when I upgraded the radiator, pulled the mechanical fan and put in dual electrical fans.
I've got an s13 redtop. Here are my motor mods:

approximately 60k miles on the motor
blitz 3" downpipe
blitz intake
blitz BOV w/custom hotpipe
Greddy FMIC
Gutted cat
Gp sports 3" catback exhaust
Koyo aluminum Rad.
Permacool dual 12" fans w/ adjustable thermostat
Recently changed to ngk spark plugs.
Recently changed fuel filter.

I DO NOT have a boost controller, or any type of fuel management system. Nor do I have an a/f gauges. Since the motor was swapped it has not been dyno tuned, and nothing has been done w/the fuel mapping.

I guess what I'm trying to figure out is if I need to fork out some 300-500 dollars worth of dyno tuning or electronics to monitor and adjust the fuel system. Or is there any recommendations that can help me save money.

I've always heard the rule of thumb that suggests a dyno tune or fuel remapping for every 3 or more motor mods.

Your help is appreciated.

Thanks

[MadChild]

You should try like a fuel pump from Welbro the 255 one...that fits perfectly with the 89-93 240sx or you can go with a harder route the 300zx ones. Its a little tougher to install that one. I was have the same problems you were have and I was boosting at 10PSI so you can imgine how that felt like. After i replace my stock fuel pump i haven't had a problem with it since. So give that a try and see what happens are if you want...you can get a SAFC from apexi for about 380 and the fuel pump is about 120...SRswap carries them so... good luck let me know how it worked out

[wizdom98117]

I already have a z32 tt fuel pump installed since I first did the swap. If there aren't any other suggestions I'll go w/the S-afc.

by the way, how do you learn to adjust the fuel w/the afc??

Are there preloaded settings that you use?

[MadChild]

Don't get the SAFC II yet i don't believe there are any U.S manuals for it so search for that im not to sure...but i defiantly know that there is one for the SAFC, with instructions and what nots. You can also go the ApexI web site and DL the manual. Whatever works for you if you need any help let me know...wis it also pretty funny your in duluth GA im in Duluth MN frezzin my *** off.

[Exessive26]

Just to let you know the SAF-C mk2 does come with a Thick manual. It is very complete, alittle Complicated you might say. But It covers just about every thing you will need to know, and them some:p.

[Yoshi]

are you sure it's not running excessively rich? YOu didn't mention a FPR in there with your mods, and the z32 pump goes full flow all the time doesn't it? (I could be mistaken, but when installed w/an SR computer at least, I think that's how it goes).

Either way, you're describing the symptoms that I had, and it was the fact taht I was way rich. Make you sure you know which it is before you hurt something! Dyno if you can... but you'll need something to adjust your fuel either way, FPR, eManage, S-AFC, etc.

[MadChild]

Yea, I heard Emange is one of the better piggy backs out there right now, but it also goes what floats your boat..

[wizdom98117]

what symptoms would I notice??

It feels like it's running really lean. How can I determine the status of it??

Thanks

[MadChild]

Yea, man i just read your mods the BLitz BOV will diffently blow some smoke out (BLITZ IS OPEN ON RECUICLATED) and a gutted cat doesn't help that either. But a SAFC would diffently tell you if your funny rich or not. DOn't waste your money on a A/F guage...

[wizdom98117]

thanks for all the help by the way...

If it is running too rich, are you saying I can fix that by getting an FPR? Will the FPR also help w/leaning out? It should if I understand correctly.

What I might do is get an FPR and see if that can solve the problem. If not, then I'll get an S-AFC.

Any other suggestions?

also, what type of FPR do y'all suggest for a full-time student budget?

Thanks

[MadChild]

you should do more research on the FPR...some doesn't work as well as the others i mean if you have the money go ahead and get the SAFC it well worth it.

[sykikchimp]

I didn't think the SAFC could read A/F?

[MadChild]

Do you know what i stands for...I believe it stands Super Air Fuel Control SAFC

[Exessive26]

The Apex'i SAFC can't read A/F.

[sykikchimp]

Originally posted by Exessive26
The Apex'i SAFC can't read A/F.

Yeah, thats what I thought.

it's Super Air Fuel Converter. It allows you to adjust the amount of fuel being dumped into the system by adding or subtracting percentages to the MAF reading.

To properly tune the SAFC you need to put the car on a Dyno with Wideband o2 so you can see the A/F and adjust it accordingly.

[Exessive26]

This man speaks the truth!:D Wideband O2, and the dyno are deff the way to go. And anyone who says a A/F gage is good to tune with is a :mrmeph:.

[MadChild]

Haha Thanx man...I'm just saying if that kid wanted to see if he was running rich or lean he should get a SAFC...by no means its better then a dyno. Cuz on a dyno you can see everything especially if you have that wide band 02 sensor that would you a lot.

[sykikchimp]

Originally posted by MadChild
Haha Thanx man...I'm just saying if that kid wanted to see if he was running rich or lean he should get a SAFC...by no means its better then a dyno. Cuz on a dyno you can see everything especially if you have that wide band 02 sensor that would you a lot.

what we're saying is that an SAFC can't tell you if your rich or lean.

[Yoshi]

Originally posted by MadChild
Haha Thanx man...I'm just saying if that kid wanted to see if he was running rich or lean he should get a SAFC...by no means its better then a dyno. Cuz on a dyno you can see everything especially if you have that wide band 02 sensor that would you a lot.

what sykik said.
no matter what, you should throw the thing on a dyno to tune it whether you get a FPR, S-AFC2, or full-on piggyback fuel management system, you still need the dyno to show the numbers and to tune... any other way is just guess and check; a shot in the dark.


edit: I listed the 3 suggestions (FPR, S-AFC2, or full-on piggyback fuel management) in order of both adjustability as well as price. the FPR will be cheapest at around $120 or less, its linear, so adjustment should be made for WOT... having it adjusted for idle may lean you out at WOT... then POP! S-AFC2 give you a full fuel curve with 12 (I think) points to adjust, piggyback systems will give you the best tunability and monitoring tools, but cost the most. You should also have a Fuel pressure gauge so you know how much fuel is going through... if you're at 45psi or something at idle, that's prolly your problem ;)