I want to get and install an efini Y-pipe but don't know if I am breaking the 3-mod rule. I already have a downpipe, cat-back, and Apexi Power intake. Since I'm messing with the air flow, will this mod affect my fuel being too lean or rich? I don't feel like getting an upgraded ecu just yet. Also, will it be bad to install underdrive pulleys being the 6th mod. This is sort of what I'm doing. I'm trying to hit 300rwhp.

1. Catback - done
2. SS downpipe - done
3. Intake - done
4. Vacuum hose replacement - I'm working on them now.
5. Efini Y-pipe - if stock ecu will allow
6. Underdrive pulley set
7. Upgrade ecu
8. SMIC
9. Midpipe
10. Suspension and wheels - shocks/springs or coilovers, sway bars, strut bars, etc.

I'll probably add a boost controller into the mix. I've done my reliability mods except for replacing the ast. I'm leaving the radiator stock for now. I guess I'm thinking that while I'm tinkering under the hood, and messing with the hoses, I might as well replace that. I am also having boost problems, but that is another post.

Thanks,
Jason

 

I think you need an ecu. If I remember correctly most people see an additional 1 lb of boost with the y-pipe. I think this with your other mods might run the car a little lean. I would save the money and put it towards the ecu. Don't make the mistake I did. Get a good ecu initially, such as the Power FC, don't go with an upgraded stock unit. The power bug will never end and this will limit you in the future and trust me, you will end up losing money in the long run.

 

you could get away with doing it only if you do a boost controler. Even if it is just a cheap home depot one until you get an ecu. I have a cat back, down pipe and k&n and I would see 12 pounds so I installed a home depot setup.

 

Hey Guys,
What is a "Home Depot" unit? Okay I'm sorry I've been seeing it in the forums but I was too embarresed to ask! Well I'm ready for the ****!

 

it's a home depot made boost controller. get the valve at home depot or lowes and the vacuum hose at an auto store. http://www.rx7turboturbo.com/robrobi...controller.htm

 

Those mods WILL get you to 300rwhp on a good engine, I just hit 306 rwhp w/ 275 rwtq this past weekend and my FMIC, Ypipe & pulleys aren't installed yet.

You may want to consider an upgraded fuel pump, they are pretty cheap insurance. Keeping the fuel pressure up on the stock fuel pump sounded too risky for me to push 300rwhp reliably.

As you can see from my a/f ratio's, I was rich with the denso fuel pump, even after pulling the PIM's down almost 10% from 4k - 8k.

http://flathat.woodstream.net/RX7/Dyno/P4210120.JPG -- hp/tq (13.5psi [.95bar on PFC])

http://flathat.woodstream.net/RX7/Dyno/P4210123.JPG --a/f

BTW: This was with the PFC basemap, changed only for boost/wastegate control and poor mans fuel control (PIM voltages) since I don't REALLY know how to tune.

I've got a few tuned maps for the mods I have that I've downloaded and will be mulling over and comparing, then when I get the guts, testing out...

K

 

Thanks jmo87