What to get: Keydriver Chip or Fuel Pressure Regulator?

[gogeta690]

I need some help on deciding what to get: keydriver chip or a FPR?I have a 92 GST. I am going to be tunning my car in mid January and wanted some feedback from anyone one which would be a better on the long run. I only have cash for either one. Here are my mods:
B16G
Supra SMIC
650cc
2g Mas
2 1/2 turbo back exhaust
255HP(fuel pump)
Greddy EGT
Air/fuel gauge
Apexi(pen)timer
Boost gauge
Apexi S-AFC

Car is running way rich @19psi.About how much boost can I run on 91-octane safely? I want the car as a daily driver but little more fuel economy. Which would be a better choice right now or easier to tune? Any feedback would be great. thanks

 

[Mike1992]

AFPR, theres nothing to discuss here

 

[oldman]

Two different mods with different purposes. AFPR is to prevent fpr overrun, eprom setup is to properly compensate for your 2G mas, injectors and injector deadtime along with all other goodies. In case if you're wondering, an eprom will not solve your fpr overrun.

 

[oldman]

nevermind my previous post, always read the entire post before responding. My vote is afpr as well.

 

[sweet97]

Do you have an EPROM ECU? You would need to get it socketed if so. AFPR first. Gotta control the fuel overrun. Then you can do a lot with a Chip when your budget allows. Mark

 

[Wanted:SWGSXAWD]

Like others have said the AFPR would be great to do now and a Stage III Keydriver chip would be great to do later . The fuel injector comp and stutter box are some of the fun stuff you get with the chip and will make your launches easier too . I got my stage III chip socketed and installed for $180-$185ish and the turn around time was barely over a week (Cali to Florida and then back ).

 

[Talesin]

AFPR. Running a 255HP for too long on the stock FPR can damage your injectors... previous owner of my GSX killed a set of stock 450s that way, thanks to the overpressure from the extended over-run.

 

[gogeta690]

Alright guys, I guess everyone is saying to go with a FPR first. One more thing, how much boost can I run with my setup on 91-octane and properly tuned? thanks for the feedback, it really helps me out.

 

[sweet97]

Too many variables to answer the boost ? but a ballpark figure would be 12-14psi. Jeff at DSMchips.com can do some amazing work on his chips and should be able to help you gain some power when you get that. I have a friend with an upgraded sidemount, big 16G, exhaust and IC pipes that with one of Jeff's chips ran a 12.57. He was at 14.0 and Jeff's chips have gotten him to that 12.57 though it is on a race gas mix. Mark

 

[Quasimondo]

Alright guys, I guess everyone is saying to go with a FPR first. One more thing, how much boost can I run with my setup on 91-octane and properly tuned? thanks for the feedback, it really helps me out.

Boost 'til it knocks, then crank it back a bit. Finding max boost is a matter of trial and error along with trying to find the right amount of tune.

 

[andymoraitis]

Mark's right and after the AFPR goes on, I can help with custom map settings for the chip. What made the biggest difference in getting from that 14.0 to the 12.57 was change in A/F from 9.5:1 to 11.7:1 and a change in timing from 16 to 23 degrees of advance. FYI, this wasn't on pump/race, but pump and octane booster at 24psi. Once the cams go in, I'll add all race, take it to 26psi and shoot for 12.20's on a sidemount and no AFC.

Hope that helps,

Andy

 

[andymoraitis]

Alright guys, I guess everyone is saying to go with a FPR first. One more thing, how much boost can I run with my setup on 91-octane and properly tuned? thanks for the feedback, it really helps me out.

The correct way to tune this would be do as advised above. Add bost until you see knock on the logger and then back the boost down so that you're not seeing more than three counts on a third gear pull. Tuning for zero knock is still on the rich side, however you should treat three counts as the edge of your tuning envelope. Considering how much you're currently taking out with the AFC, I don't see why you can't run the same amount of boost as you're running now, just on a better tune.

Let us know how it goes,

Andy

 

[gogeta690]

Alright guys, thanks for all the info!! I have talked to someone at RRE and I will be getting my car tuned in Mid January. As soon as I get it tuned back to the race track or the dyno. I want to be around 270whp atleast. I think I can pull it off. Well i will be posting up results asap. But thanks for all the info and feedback.

 

[DROOPY209]

AFPR is the logical choice right now for you to compensate for the air/ fuel ratio you currently are experiencing.

I hope you have your keydiver chip in before you tune the car as well.

 

[oldman]

Alright guys, thanks for all the info!! I have talked to someone at RRE and I will be getting my car tuned in Mid January. As soon as I get it tuned back to the race track or the dyno. I want to be around 270whp atleast. I think I can pull it off. Well i will be posting up results asap. But thanks for all the info and feedback.

RRE is a great DSM shop, however, they seem to be the only DSM shop I know that continues to push B&M Command Flow although it has been established long ago that it does not work for DSM. I don't know if they have changed their view on the subject of AFPR since the last time I spoken to them which was 2 years ago, do not buy the B&M unit even if they insists that it will work because it will not.

 

[97gstnick]

AFPR. Running a 255HP for too long on the stock FPR can damage your injectors... previous owner of my GSX killed a set of stock 450s that way, thanks to the overpressure from the extended over-run.

sounds like b.s. to me. i ran a 255 with no afpr for a long time and nothing ill happened

 

[sweet97]

I can't say about killing injectors but when I put my Walbro 255 in I could not boost at all as it would run so rich. mark

 

[DSM90AWD]

RRE is a great DSM shop, however, they seem to be the only DSM shop I know that continues to push B&M Command Flow although it has been established long ago that it does not work for DSM

Works fine for the stock pump => 190LPH but not the 255LPH+ pumps

A 255HP pump will not kill injectors. Running > 100% IPW for extended periods will (and likely your engine too)