Advice on desired exhaust setup/tuning?
 

Before I jump in and spend $1500, I wanted to seek the experience of the forum. My goal with any mods will be to either remove weight or increase power (both preferably). Eventually I may pursue other mods like suspension, but I just DD for now. I currently have Tomei 60R (-30lbs ish, +?hp). I'm looking to do HKS dual resonated front pipe (because I saw confirmed fit with auto) and Tomei overpipe. This will only shave a few lbs but I figure the dual resonated will quiet down some for the end goal (Tomei UEL). Plus it shows 60mm diameter and the Tomei is 60.5mm. Once I get to the Tomei UEL, I know I'll need a tune. I'll likely go with the OFT. I saw someone confirmed with Torque that it gives ready/complete on the O2 ( Illinois emissions concerns). Overall this should shed 45-50lbs and give me good gains below the curve between 1k-5k. Having laid this out, can anyone offer advice on something I may have missed or something that could be better? Are the issues I've read about with with OFT uncommon? Im hoping my 93 is good enough to run the stg2 uel without having IAM issues.

It'll be louder and raspier ditching the cat in the frontpoipe. That'll get even worse with a header, and you'll be able to smell the lack of a cat.

Otherwise, sure... Reasonable plan. 93 and OFT should be fine. Emissions, I sure hope so (though I have a cat in the frontpipe and need it to be autocross class legal).

C

What issues with OFT have you read about?

I've read about people needing to drop down to the 91 tune from the 93 because they weren't able to maintain the ideal IAM (which I would probably monitor constantly given my OCD). I understand they're one size fits most tunes, so I was just curious if the majority of people run the stg2 uel 93 without issue. The way I figure it is that if everything is going great, people don't post and it's mostly when things aren't going great is when they do (which might make things seem like issues that generally aren't).

I think you will find that you have figured the situation out. If I recall some of those guys with issues had other things going on as well but refused to check beyond the tune.

Local friend runs OFT and OFH and he switches between the 93 and 91 tunes. On the dyno, the 93 tune gives around 10whp more, but he says the car feels weird (butt dyno) on the 93. This is using Petro Canada 94 gas (10% ethanol). I think he runs the 91 tune most of the time.

When you get a header, choose one with a flex pipe. I've seen pics of aftermarket headers cracking which don't have a flex pipe. Pay the extra for heat wrapping so that you don't cook your coil packs. Under hood temps will increase a lot if you don't coat or wrap. When you coat (if you go that route) make sure the exterior AND interior of the pipe are coated. Don't re-use the header gaskets, get the Grimmspeed header gaskets- they are cheaper and better than the OEM header gaskets. I re-used the other gaskets and I have had no issues.

An intake will give you a small gain in power (if you choose the right one), they look good and sound good but for sheer power/dollar, they aren't worth the money. That said, they do give you a little more power on the dyno. that said, some are better than others and some actually DECREASE power, so look for tests there are plenty on this forum and a big intake showdown on DSport Mag's website.

I read different things about OFT, but I have had no probs with mine at all. I love it and at any time I can revert to the stock tune and no one is the wiser. I will sacrifice a few HP for flexibility. My LTFT is very good and AFR is great.

If you go catless and do a Stage 2 OFT tune, you WILL fail your emissions test. Stage 2 disables the P0420 MIL. Stage 1 does not and if you are keeping the cats, that's the tune you want anyway and you'll pass emissions. When you do your Stage 1 tune, wait a week (drive the car normally) before you go for emissions testing.

The 93 tunes are only different above ~5k rpm under heavier throttle. If he's feeling differences around town, it's probably in his head.

Hmm im not sure if he was refering to track or town usage, I will ask.

Thanks for the advice on coating/wrapping. I was planning on at least wrapping the header because I doubt that small section of shield they give you to stick on the oil pan does enough.

Are you saying I can flash to the stg1 tune to pass emissions when the time comes (in 2020)?

Also, by flexpipe are you referring the the longer sections on UELs I see with them? Would it not be as much of an issue with an EL that doesn't have flex sections?

UEL header and that Tomei catback will be brutally loud...if you change out the front pipe, it will be even louder. Unless you want the loud to be uncomfortable above 65 on the highway.

Also, I would steer clear of the HKS front pipe with your setup...the whole pipe is like 2.3" or something. Get a bigger FP that cuts down on noise and won't restrict your exhaust flow.

I figured the HKS at 60mm was closest to the Tomei at 60.5mm. As far as loudness, I'm not super concerned about that yet as I rarely drive on the highway and because racecar. I figured if I went full catless I could tune out the cold start high rev (which I believe is only in place to warm up the cats?). It seems like cold start is where a lot of the videos show excessive loudness.

Ask your neighbors. Really, i have seen ppl ditching expensive exhaust set up because neighbors.