Modified Stock Parts Build?

[FRS86edition#3]

I have done a decent amount of homework, and I have found some bits and pieces of information, but I wanted to see what the community had in shedding more light on this.

Here is what I have been brainstorming.

1) Modify stock header/manifold. I found little information specifics on this. I found only one small thread on this. My thoughts are for $500-$800 I can get a really nice header, but the stock header is a nice design. Most restriction seems to point towards the cat. I am thinking of cutting the cat out, not gutting it, literally cutting it off and then welding a straight pipe OR straight pipe with a braided flex pipe too. Thoughts on this? I was thinking about having it ceramic coated too and ditch the heat shields.

2) Front pipe modification. Straight pipes can be had relatively inexpensively, but what about taking the stock front pipe and cutting the muffler and cat out an then welding straight pipes in there place.

I like the thought and challenge of modding these parts for very minimal amounts of money, while netting similar results to aftermarket units.

All I am looking for is some torque increase and better driveability scooting around town. I want to feel pushed back in the seat more.

I realize a tune will be required, and I was leaning towards OpenFlash Tablet. I live in the middle of nowhere Indiana where a dyno is NOT located closely.

Do you guys think running a tune for aftermarket header and FP would work on the modified stock parts? E85 and 93 are readily available here too. I am thinking there could be some noticeable gains from doing these upgrades. Maybe 190whp (e85) and 160 ft lbs?

I think this could all be accomplished cheap. I am working with a few members to buy some stock parts to practice on.

Other than the OFT cost, really, there is not a whole lot of expense. $21 header gaskets, $34 for new exhaust gaskets, exhaust joint sealer $3. I have all the welding equipment already. Adding a K&N drop in, modding the stock air duct, and maybe an intake pipe could maybe get this car to decent numbers and all for hopefully under $500.

Any thoughts, insight, or opinions?

[SomeoneWhoIsntMe]

how do you make payments on your car if your budget for a header and exhaust is $58?

not to mention that cutting the cats out of a brand new otherwise stock car to pick up 5whp is arguably kind of a **** move.

[Koa]

Originally Posted by SomeoneWhoIsntMe

how do you make payments on your car if your budget for a header and exhaust is $58?

not to mention that cutting the cats out of a brand new otherwise stock car to pick up 5whp is arguably kind of a **** move.

grumpy this morning sir

He likes the challenge of modifying OEM parts to give aftermarket gains.. nowhere indicative of his fiscal position or ability to maintain a good fiscal standing..

--

I used an M80 to blow out the cat of my WRX stock downpipe, gutted the front cat pipe, and ran that for over a year, tuned by XPT stage 2. The results were similar when I switched out for a true 3-inch TBE solution. I like the approach- minimal environmental and financial impact while maximizing value. That's the dream. YMMV

[DAEMANO]

Originally Posted by SomeoneWhoIsntMe

how do you make payments on your car if your budget for a header and exhaust is $58?

not to mention that cutting the cats out of a brand new otherwise stock car to pick up 5whp is arguably kind of a **** move.

@SomeoneWhoIsntMe
Be nice.


@FRS86edition#3
1) There's a thread where someone ( @NickFRS ) cut out the stock cat and welded in a straight pipe (link below). Dyno'd it versus his RevWorks ELH and It basically performed the same. Which is also pretty much the same as every other aftermarket catless ELH. So could be a good mod for you. I was able to buy a stock header from a board member for about $100 and kept my stock header set aside, so go for it. http://www.ft86club.com/forums/showthread.php?t=55770

2) If you ditch both cats, be prepared for some rasp and drone. Otherwise this should also work IMO.

3) Yes, the off-the-shelf OTS (Stg.2 pump gas, and e85 tunes) from OpenFlash should work with this setup. An OFT tune with e85 could get you to 200WHP / 170ish WTQ. The car will feel a lot more aggressive and the torque dip will be gone. It's worth every penny for that alone (not counting the logging, digital gauges, and more).

With enough research and skilled people to do the work, your approach can work. Make sure to change those gaskets, and I wouldn't remove the heat shields because the exhaust is routed around the oil pan which is likely a contributor to some of the heat related issues peeps have with this car. Also they help to keep the noise down, something a coating or wrap will do less of, plus they maintain a stealth OEM look. Lastly, don't be put-off by jerks, mod on.

[Bobblehead]

Please correct me if I'm wrong, (it happens a lot) but isn't our header a cast piece? That would make it difficult to put a new pipe in in place of the cat.

That said, I'd prefer to have an exhaust shop make the new front pipe instead of ripping the stock one to shreds, but that's just me. Other than brazing, I can't weld.

Good luck!

[2016 Camaro SS]

I will put my JDL UEL up against a modified stock header any day. Just talk to a tuner and they'll tell you why it matters. Exhaust scavenging is still limited with the stock manifold.

[SomeoneWhoIsntMe]

@Koa maybe I'm being a grumpy goose today but I mean, I feel like this is borderline irresponsible. it's not like this is a WRX / supra / whatever turbo car where a test pipe and tune nets you huge gains, or a 20 year old beater with a leaking exhaust and a half plugged cat and it'd be $800 to replace the cat or $50 to weld a pipe in place of it.

yeah, on a 02 WRX with three cats including one pre-turbo, just cutting the cats out got you relatively major gains. that's apples to oranges though, since his FRS doesn't have a turbo. surely on an N/A car, the piping diameter, bend radii, and merge collectors play an important role, moreso than just cutting the cats out of a stock manifold.

it just seems troubling to create an exponential increase in the car's emissions for an incremental bump in horsepower. maybe if you're running E85 all the time it's not a huge deal. idk.

[FRS86edition#3]

In response,

1) I have no issues paying the car payment. LOL. That was a little speculative.

2) @DAEMANO , thanks for the input! This is more of what I wanted the thread to be about. You are 100% right, its all about the challenge and ingenuity. It is cool to get, for the sake of argument, "similar" results to aftermarket parts while spending a fraction of the cost.

3) In Indiana, I do not have to worry about emissions (not legally at least). I understand sustainability and protecting the environment though.

4) I will be keeping the integrity of my OEM parts. I am buying used stock parts, so when I get rid of my car I can simply convert it back to stock just like all other intelligent modders do.

5) I think @DAEMANO is right too based on what I have found. Doing these mods with an e85 tune will probably push it close to 200whp, but really, I care more about the torque increase.

Once I get OFT from @slofrs (pending sale), an FP on ebay for $60 shipped, and hopefully a header for around $100 shipped, my total spend will be around the following hopefully:

Header: $100
FP: $60
OFT: $400
Gaskets: $55
Total: $615

So for the cost of a Borla header, I will hopefully be able to put down power for a lot cheaper than most. Is that not cool or exciting? I will definitely take pictures and share my build with others.

[steve99]

Modifying stock header should work.

OFT tune was done for aftermarket catless EL headers. But does seem to work well on various brands of catless EL headers (as does their UEL tune for UEL headers).

It probably wont be optimal due aftermarket headers having different pipe sizes and runner lengths.

Given that the OFT Stage 2 EL header E85 tune has been used extensively on the stock header by many with good results again it should work.

just log the results check your AFR and for knock .

[ineedboost]

I'm running a stock header that's modified exactly as you describe, save the flex section. It's worked great for me. My car is tuned with an OFT. I've run both the stage 2 EL and e85 EL tunes with no issue.

I did this because I scored a stock header for $150. My total investment, including a new flange, o2 bungs, and a section of 2.25" pipe was like ~$170. Plus I recycled the cat so my net cost was around $120.

[Koa]

Originally Posted by SomeoneWhoIsntMe

@Koa maybe I'm being a grumpy goose today but I mean, I feel like this is borderline irresponsible. it's not like this is a WRX / supra / whatever turbo car where a test pipe and tune nets you huge gains, or a 20 year old beater with a leaking exhaust and a half plugged cat and it'd be $800 to replace the cat or $50 to weld a pipe in place of it.

yeah, on a 02 WRX with three cats including one pre-turbo, just cutting the cats out got you relatively major gains. that's apples to oranges though, since his FRS doesn't have a turbo. surely on an N/A car, the piping diameter, bend radii, and merge collectors play an important role, moreso than just cutting the cats out of a stock manifold.

it just seems troubling to create an exponential increase in the car's emissions for an incremental bump in horsepower. maybe if you're running E85 all the time it's not a huge deal. idk.

There we go, that's the knowledge right there.

[zooki]

Kudos to you sir! This is old school hot rodding. Like some of the others said, score a used stock header, maybe the whole exhaust, for cheap and start cutting & welding. May work, may not, but it'll be informative to try.

[kodyo]

I like the idea of modding stock parts so I say go for it. Two comments:

1) don't ditch the heat shielding if you can avoid it. I wish I could have kept it for my aftermarket header. It will keep engine bay temps down, oil temps down, and protect a few critical electronic components.

2) the best mod I've done for my car is the 4.56 diff swap and I have An aftermarket header/front pipe/over pipe/axle back/drop-in/intake tube. So if you can save up for that first, you won't regret doing that mod over the tune/exhaust route. There's a DIY here that I wrote about the diff swap in and it can be prett economical ($1k or less) if you buy supra mark 3 gears instead of the brand name FRS gears that are a rebranded rip off.
http://www.ft86club.com/forums/showthread.php?t=54054

[FRS86edition#3]

Originally Posted by kodyo

I like the idea of modding stock parts so I say go for it. Two comments:

1) don't ditch the heat shielding if you can avoid it. I wish I could have kept it for my aftermarket header. It will keep engine bay temps down, oil temps down, and protect a few critical electronic components.

2) the best mod I've done for my car is the 4.56 diff swap and I have An aftermarket header/front pipe/over pipe/axle back/drop-in/intake tube. So if you can save up for that first, you won't regret doing that mod over the tune/exhaust route. There's a DIY here that I wrote about the diff swap in and it can be prett economical ($1k or less) if you buy supra mark 3 gears instead of the brand name FRS gears that are a rebranded rip off.
http://www.ft86club.com/forums/showthread.php?t=54054

This is ironic! Lol. It was slow at work today, so diff mods/gears were what I was looking up. The Cusco ones are rather pricey. I will definitely look into the Supra idea. Awesome info! Thanks again!