Next round of mods...need more fuel yet?

[JBones81]

Car is 2012 WRX sedan:

Currently, I have the Cobb SF intake/box and their ots stage 1 on accessport, and the nameless performance muffler delete setup. I'm gonna order the cobb catted dp, and do the stage 2 map...was also really leaning toward doing the process west top mount ic, and then getting it pro tuned. If I'm gonna go beyond the dp and stage 2 to add the tmic and protune, do I need to start upgrading the fuel system at all prior to wrapping it up, or am I ok unless I go beyond the listed mods??

fwiw, I'm in Northern CA and can't get better than 91 anywhere...and it's tuned by cobb on that AZ, NV, CA tune cause apparently our gas is that bad

thoughts at this point in mods??

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[GrumpyPitbull]

Your going to get differing opinions on this. Its a support mod, so many people feel you should not do it unless absolutely necessary.

Me personally, I would check the idc and if it is over 90% I would upgrade the injectors and pump. My feeling is if you going to spend thousands on parts .. why not spend an extra 500 or so to ensure your fuel system is up to snuff.

You will likely be around 95% at stage 2 with a tmic .. some have even reported being at 95 with just a stage 2 ots map. I suspect it is one of the reasons we see so many pistons popping on stage 2 cars ... But that's purely my own speculation.

[HinshawWRX]

Your injectors will be CLOSE to maxed, but not enough to require injectors.

So needed? No. Decent upgrade before a protune to ensure room for growth? Sure.

[xluben]

Originally Posted by HinshawWRX

Your injectors will be CLOSE to maxed, but not enough to require injectors.

So needed? No. Decent upgrade before a protune to ensure room for growth? Sure.

Agreed.

[drewvdw]

What these guys are saying. After tuning a few 09+ WRX's my tuner highly recommended fuel pumps and injectors to go in with an intercooler and/or downpipe.

[xluben]

As long as you have a good tune you should be fine. The fuel system will probably be the limitation, but the extra $500 you'll spend on fuel will probably only get you 5% more power at most. Worth it if you're going for more later, but maybe not if this is all the further you want to mod.

[thisisntjared]

Originally Posted by xluben

As long as you have a good tune you should be fine. The fuel system will probably be the limitation, but the extra $500 you'll spend on fuel will probably only get you 5% more power at most. Worth it if you're going for more later, but maybe not if this is all the further you want to mod.

i agree with this. if you were to go e85 or get a bigger turbo, that is when you will be genuinely annoyed with your current fuel ceiling. but until then, and especially if you are not having a custom tune on a dyno, the limits of your current fueling wont aggravate you.

you could just wait to upgrade fuel at the same time you have a custom tune done for other big power upgrades

[JBones81]

ok, so I get that upgrading fuel components would be a solid move, pending future upgrades, but now I'm concerned (from reading response above) that I'll be so close to maxxing my stock fuel system's capabilites just with a downpipe and stage 2...

before starting this thread, I hadn't heard this concern. Should I be worried?

[HinshawWRX]

No, no need to be worried. Remember, you will be CLOSE to "maxing out" based on Stage 2, but doesn't mean you NEED to replace anything if you don't plan on going bigger.

[tunertype]

at stage 2 your injectors at 95% can provide all the fuel you need. with the intercooler you might be able to push alittle more boost and could get to around 100% IDC. your car will run like this fine until the injector gives up.(think how long a stalled drill will last if you keep giving it power... about 1 minutes and then burn fire death). Anything over 80% hurts the injectors reliability, but upgrading injectors when your at 95% will net you 0hp gain only increased reliability.

i would upgrade the injectors if its a DD. if its a weekend or track car keep stock injectors. also you really don't need to upgrade the fuel pump, but most do when getting injectors at $80 its cheap insurance. and you don't need to go crazy 650cc would be plenty. also if your cheap you can get a fpr and your 560cc can flow 605cc @50psi.

[Leafy]

Originally Posted by tunertype

Anything over 80% hurts the injectors reliability, but upgrading injectors when your at 95% will net you 0hp gain only increased reliability.

I wouldn't quite say that. Some big race engine shops like Rebello believe that when the fuel injector is open you are blocking a little bit of air flow, ie a long injector duty cycle hurts power. HOWEVER, I also have never seen any data for or against this theory.

Another thing that could explain why their theory is caused; since you're maxing out the injectors to hit you targeted afr you could have very different afrs on different cylinders just from the manufacturing tolerances of the injectors, which would effect power. This does happen.

[thisisntjared]

Originally Posted by tunertype

i would upgrade the injectors if its a DD. if its a weekend or track car keep stock injectors.

this only makes sense at surface value where daily drivers must be reliable and track cars may be as rigorously required to be reliable. a daily driver is floored to redline occasionally. a track car is floored to redline at every given opportunity. so which is going to push the injectors harder?

anyway, an OTS stage 2 map should not require any fueling upgrades. i know its a different car, but i ran the cobb ots stage 2 map on stock fueling for 2 years with no problems and complete peace of mind.

[Leafy]

Originally Posted by thisisntjared

this only makes sense at surface value where daily drivers must be reliable and track cars may be as rigorously required to be reliable. a daily driver is floored to redline occasionally. a track car is floored to redline at every given opportunity. so which is going to push the injectors harder?

On the flip side, which one ****s you more if it breaks? Race car you just winch back onto the trailer, daily you ride your bike to work.

[Dave D.]

If you are going to go bigger on the injectors, I'd recommend something that will also support a larger turbo -- I'd say 750 at least. If you go, say 20g or more in the future 750 may even fall a bit short. No point in replacing injectors twice, IMO.

But I also think you don't need bigger injectors for what you are planning to do.

(Speaking from experience. My hta68 was starting to max out my 725's -- now running 1000's.)

[thisisntjared]

Originally Posted by Leafy

On the flip side, which one ****s you more if it breaks? Race car you just winch back onto the trailer, daily you ride your bike to work.

no you just rent a car. both suck, just one environment increases your probability of disaster.

[JBones81]

this is my daily driver...I just want the most power I can get without really affecting reliability.

My last car was an 08 c6 corvette, (actually, last car was an 03 SRT-4...but it sucked) and I was able to find a great balance between power and reliabilty by doing all the intake/exhaust mods and a tune. The car ran great, (11.6@123mph, 32mpg on the freeway) and nothing broke. I know this car won't be deep into the 11s with bolt ons, but like I said, as much as possible without hurting the car is all i'm going for here.

thanks guys,

[06sc0obySTI]

not really needed but def think about bigger injectors and fuel pump in the near future. im running 1000cc injectors which is a little OD but whatever and a walboro 255 fuel pump which is working great for me