Best way to tackle the torque dip
 

What is the best way to smooth out the torque dip without going FI?

Will OP help first ?

Or should I just start from Cat-Back and work my way to the headers?

Headers + Tune, Shiv has a good solution if you like the UEL sound

The simplest way to eliminate the torque dip is FT86SF's catted UEL header. It's catted (i.e., no CEL), and you don't need a tune to completely eliminate the dip.

http://ft86speedfactory.com/images/f...ldynoSTOCK.jpg

This is with header only, no tune. Note that torque rises at 3200 rpm, where the dip traditionally begins.

I like Vishnu's OFT + OFH and think it's the best value tune/header at the moment, but it doesn't completely eliminate the dip. It's still partly there starting at 3200 rpm. Much better than stock though.

Yeah I was looking at FT86 Cat Headers a little later on.

If I was to do that

FT86 Cat Header -> Invidia OP (Depending on peoples review of fitament) -> ARK Test Pipe -> ARK DT-S

a header and some cam timing adjustments seems to be pretty effective in eliminating the torque dip.

HUH? Why would someone spend $950 on that header when you can spend practically the same exact amount of money and get way more performance with no worries of CELs? Theres no dip in the area you are referencing, just the same fluctuations that the catted header you are comparing it to, except the OFH and OFT on E85 is producing 25 more HP and TQ.

Save your money on the rest of the exhaust, they add relatively little performance gains for their comparatively extreme cost. Get yourself a header and tune, put the rest of that money into something that will add actual performance to your car unless you are looking for more sound with almost no gains.

Haha calm down there. First off, post some data. And don't compare E85 to 92 octane pump.

Who's not calm? http://i85.photobucket.com/albums/k4...FHOFT91oct.jpg

You say it still has a dip, except the OFT/OFH makes more power over the entire rpm range than that catted header at essentially the same price point. I can't think of a single reason to choose that catted header over the OFT/OFH combo.

Just an initial point -- it's not "my" header, so I'm not biased in any of this.

Second, you're comparing OFH + OFT (tuned) vs. untuned FT86SF. Have to stick to apples v. apples. Once we see a tuned FT86SF dyno, you can make that comparison.

Third, you're comparing different dynos. See how the baseline on the OFH dyno was 171 vs. 161 on the FT86SF dyno? Dynos read differently. Try going by deltas instead of absolute numbers.

Lastly, see how torque starts dropping at 3200 RPM in that OFT + OFH dyno? That's the torque dip OP is trying to eliminate. See how torque rises at 3200 RPM in the FT86SF dyno? That's the solution.

I'll say it again -- The simplest way to eliminate the torque dip is FT86SF's catted UEL header.

Not sure how you can say that plugging in a device and pushing three buttons is complicated, but whatever. The point of comparing the OFT/OFH combo to that catted header is to show the OP what a waste of money it is to buy that particular header when you can get more performance at a much lower pricepoint. If you are suggesting that the OP spends the same amount of money to get less performance then by all means continue.

Even though there is a slight dip with the OF combo, its still producing more power over the entire range than that header alone is doing. Sure you can get a tune and attempt to get the same level of performance but that means even more money and you are still stuck with that cat which is the primary reason it wont match a catless header in performance. Buying a catted header is pointless.

It's not the programming of OFT that makes OFH complicated. It's eliminating a cat (potential state emissions issues) plus adding a tune (potential warranty issues) that makes it complicated. If OP wants the simplest way of eliminating the torque dip, it's FT86SF's catted header. No tune or elimination of cat required. Just install the header and be done with it.

It's a bit close-minded to think that buying a catted header is pointless. For some people who may be differently situated than you, it will certainly make sense. I probably will be going OFH + OFT bc I don't care about the torque dip that much (or emissions or warranty), but that doesn't mean it's the right solution for everyone.

+1 @DarkSunrise also note how the torque for the OFT+OFH goes from roughly 140ft-lbs down to roughly 125ft-lbs. thats a pretty good dip in torque. also note this is with the tune. of course both the dynos for both FT86SF and OFT+OFH are their own dynos and not independent 3rd party dynos.

Also I bought a FT86SF header because i live in Cali where emissions are tight and while the header is not CARB legal i can likely get away with out swapping it out down the road for emissions tests.

Dont get me wrong the OFT+OFH combo is probably the best NA bang for your buck mod atm but there is still a rather large torque dip.

Not sure how you think going with a catted header suddenly makes you legal. In case you were not aware, it is illegal to remove or replace a functional catalytic converter unless it is clogged, damaged, rusted out, missing, or lead-fouled.

Even then the replacement cat has to be certified by the EPA and required to have a EPA permanent label that identifies the type of converter, a code number issued to the manufacturer by the EPA, the application part number, and the manufacturing date. The installer also has to document the reasons for the replacement along with the odometer reading. The replacement cat has to be of the same type as the orginal, EPA certified and in the same location as the original.

Performance catted headers are no more legal than catless headers. Once you realize that, if you are going to replace the header you might as well go catless since you are breaking the law either way.

Not saying it's legal, but for most jurisdictions that have emissions (whether visual or sniffer), you'll have a better chance of passing with two cats, esp when OEM has two.