Would you consider an M2 catback, a N-Tech highflow cat AND an HKS downpipe with completely stock intake too much for the stock ecu? If so, which ecu upgrade would you recommend?

 

You might be able to get away with it, but I don't know

 

Yeah, that's what I'm thinking too ... but I need to know!!! lol

 

You've let the exhaust more free, but you've also kept the intake side stock level restrictive so It's safe to say that your engine isn't getting any air, but at the same time, how will the exhaust being more free flow affect boost? What's your boost level and what was it when it was stock?

 

Check this thread:

https://www.rx7club.com/forum/showth...threadid=94169

 

Just limit your boost to 10 psi, you can run virtually any bolt-ons with the stock ecu.

 

it's difficult to limit the boost levels @ 10psi if you have every bolt-on. You're going to see spiking and boost creep, and you any spiking/creeping reaches a high level, your motor might blow. However, if you have a reprogrammed ecu, it will compensate with more fuel, even if you do spike/creep. Unless you port the wastegate and get a good boost controller, it would not be a very good idea to mod your car without an a.f. ECU, it's pretty cheap (second hand) plus it is required if you purchase more mods in the future. why not just buy one now?

 

legendr35,

Why would someone want to use a band-aid fix (upgraded ECU to add more fuel when boost creep occurs) when he could fix the root of the problem (bore the wastegate, or use a cat or another restriction in the exhaust)?

Usually, a highflow cat is enough to prevent boost creep.

Wade

 

Really? N-Tech claims the cat has "96% of the flow of an open pipe". Damn, currently the car is running the M2 catback and the N-tech cat and I was hoping to get the dp to help control under hood temps. So what's the verdict lol... is this setup with a downpipe too much? Should I be thinking of going back to the stock cat just to be on the safe side?

 

I saw a thread somewhere (from capt bill I think) where he measured back pressure on a ntech vs midpipe and it was 7 vs. 3 (dont remember units) but if that is the case then the math would have to make the stock be around 100 and obviously that couldnt be (cause it couldnt be that bad). I think the claim of 96% is typical marketing crap that usually cant be confirmed or denied unless someone goes to all the trouble capt bill did.

Yep here the thread is:

https://www.rx7club.com/forum/showth...+pressure+tech

Not sure this actually help original post but was mainly an answer to the last question.

Shawn

 

You will be fine. I know you will be fine as far as the stock ECU and fuel are concerned.

The real question is if you will be able to control boost, and I know a lot of people with high flow (N-tech and other brands) cats, and none of them have had boost creep problems, even with higher flowing intakes and ICs. You might have to tweak your pc and wg pills/valves a bit but that is standard stuff. I'd bet money you will be fine.

It still doesn't hurt to do a fuel pressure test and/or a wideband lambda meter test periodically to make sure the fuel system is working properly.

Wade

 

I basically meant, if you want a less chance of blowing your motor caused by spike/creep, you should get an aftermarket ECU. I also stated its best to get your wastegate ported. The band-aid fix is better than no fix.

 

haha, i second the "fish tank" valve. the home depot valve is a good idea to control boost and pre-control.

You still haven't answered what boost pressure you are seeing with your current mods? and please tell me you have a boost gauge!

Danny

 

This is true!

Wade

 

I'm actually picking up the car this month, it's not mine yet . Looks like the guy modded the car backwards... he has a catback and highflow cat with no dp and no boost gauge. He also has an APEX-i intake which (thankfully) isn't installed. The rest of the car is bone stock. I'm thinking I should be ok if I get a gauge, the dp and a high performance homedepot boost controler set to 10psi, make sense?

That intake will have to wait until the ecu gets bumped though .

 

i highly suggest bringing a boost gauge with you to see how the boost characteristics are. I think a boost gauge should be one of the first if not THE first mod to put on the car. Even a stock car can have problems with boost. Basically, if you see 12-13psi spikes when you test drive it, i would stay away....

Danny

 

Yeah i would get a ecu next cause i got a dp hi flow and cb and my car is spiking to 13 psi, so for now i'm not flooring it till i get my pfc in the car

 

I ran intake, dp, catback with stock ecu and home depot racing valves for over a year with no problems. i kept my boost at or under 11

STEPHEN

 

since we are on the subject...

tomorrow I'm getting back my ECU which is being remapped by M2 at stage 3 levels for stage 2 mods (Brian recommended it for safety)

Am I understanding you correctly in saying that this is only a "band-aid" fix??? I don't want to deal with fine tuning a stand alone aftermarket engine management system.

And, it is my understanding that adding intake/exhaust mods alone will up the boost on the car, by about 1psi each. So, boost controller aside, its pretty damn difficult to limit your boost. DP and CB alone ups you to 12psi, which the stock ECU will not handle efficiently...

am I missing something????

 

It's difficult to control boost usually with a midpipe. If you have a cat, even a high-flo cat typically has enough back pressure to avoid boost creep.

Not all cars react the same to mods, so you will just need to see how your car is boosting. I had a dp, high-flo cat, cb and was only boosting at 10 PSI until I upgraded my ECU. However, there have been people that added a dp and began seeing much higher boost levels.

 

oh well, better safe than sorry i guess... the M2 ecu will be programmed to run at 13 psi.... but there will be plenty of fuel to compensate...