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01, Impreza
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Discussion Starter · #1 ·
Hi everyone, thought I'd show you what my friend and I have been working on.

We are currently making a prototype ej22 single port header that we plan to produce and sell. The prototype Header features CNC plasma cut 3/8" flanges, mandrel bends, our own Collector/Diffuser, 1.75" 16 Guage Primaries and Tig Welds all around.

In the future we will be offering these in Mild steel with a few coating options, or 304 ss. The prototype is of EL design and currently has 39" and 35" primaries. When production begins we will have the Headers Equal Length +/- 2". For all of you who prefer a nice rumble, we'll be offering a UEL design as well.





As many or you know the stock collector for the ej22 is absolute garbage and is one of the main choking points in the exhaust. Our collector solves this problem and Improves scavenging effect through the primaries. Another side effect of proper collector design is that regardless of the EL or UEL design, both Headers will have excellent performance gains. Here is a comparrison between the Collectors for all you visual learners.



Currently my colleague is home for Christmas Tig welding the headers. I'll be posting updates in this thread such as quality pictures of the final product and sound comparrison. In the meantime here's a set of headers we made for a f4i engine.





Happy Holidays!
 

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1996 imp jdm ej20 NA dohc swap
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400 Posts
This is very cool especially for the people who build a NA hybrid motor with single port exhaust heads and need a better header than stock.

I know of a guy who might be interested if this is not too expensive.

How close will the EL single port one be to the oil pan and the oil filter?

Would you be up to building a 2" OD primary piping into a 2 1/4 collector header for people who port the exhaust port larger than stock?

It seems to me you are going with a similar designed collector as the TWE NA headers if you happen to know who they are.
 

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01, Impreza
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Discussion Starter · #4 · (Edited)
We're very excited to open up options for the single port head. In terms of price we're looking at around 300$. That includes gaskets but not shipping. That price may go down depending on the level of interest.

The header sneaks right past the oil pan. It may look close in this picture but there's room to do an oil change without taking the headers off, the centre jacking point is also left open. Clearance is the same as stock.



When production starts we will be offering an excel type spreadsheet with all the options for the headers. Customers will be able to fill out the spreadsheet to show the exact header they want and a price will be calculated for you.

We can absolutely do an option for larger primaries, thanks for bringing that up. In the future we plan of offering a header which replaces the first Cat with one that points straight ahead instead of bending to the drivers side. Like larger primaries we will incorporate this to the order sheet with options for a high flow cat, Track pipe and straight through cat look-alike.

Edit: Have never seen a TWE Collector, will have to look into that!
 

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98 Red OBS
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Nice! Just my 2cents, Wouldn't it be a good idea to add a flex joint on both runners this way it has slack if the engine shakes or jumps. I've seen plenty of headers crack because they don't have wiggle room.
 

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98 gc coupe L
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127 Posts
nvm i see the price so how long will it take to have them shipped? do u have a extra set of headers already? pm me am very interested thanks
 

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Discussion Starter · #7 ·
Nice! Just my 2cents, Wouldn't it be a good idea to add a flex joint on both runners this way it has slack if the engine shakes or jumps. I've seen plenty of headers crack because they don't have wiggle room.
There are several reasons why we did not include a flex. First, to keep cost to a minimum. Second, we feel it isn't necessary.

Most headers that crack (such as the borlas) are due to stresses that are induced from heat expansion. The factory headers have no flex and do not have issues with cracking from vibration. If you observe the way the passenger side primary loops around, think about how the tubes will expand from heat. The amount of stress in the primaries should be negligible. I can draw a diagram if you'd like!

A lot of headers also crack because of poor welding practices. 304 stainless needs to be back purged properly otherwise the weld is compromised. It is also more sensitive to heat than mild steel. If too much heat is put into the material during welding, chromium will precipitate out of the weld leaving a brittle area within the heat effected zone that is prone to corrosion and stress cracking. This is a good reason why true high quality race headers will use 321 stainless and not 304, though if a car isn't going to see the track or repeated dyno pulls 304 is usually fine. This is also why we chose 1020 mild steel for our basic headers. No MIG work on these bad boys, any header we complete will feature TIG welds.

It is likely that our catless systems will include a flex in the exhaust where the cat used to be. Because of the design of the stock replacement headers, we would have to include a bellow in each primary, which we could do for the cost of the bellows. That said, replacing worn out flex's is no fun either, something to consider.
 

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Discussion Starter · #8 ·
nvm i see the price so how long will it take to have them shipped? do u have a extra set of headers already? pm me am very interested thanks
We are not sure yet when these will be available. It really depends on how much interest we get. I'm an engineering student as well so free time is limited, it is likely we will be making a materials run and starting production in a few weeks. Without enough interest, this might not happen so get the word out to your Subaru buddies!
 

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98 Red OBS
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There are several reasons why we did not include a flex. First, to keep cost to a minimum. Second, we feel it isn't necessary.

Most headers that crack (such as the borlas) are due to stresses that are induced from heat expansion. The factory headers have no flex and do not have issues with cracking from vibration. If you observe the way the passenger side primary loops around, think about how the tubes will expand from heat. The amount of stress in the primaries should be negligible. I can draw a diagram if you'd like!

A lot of headers also crack because of poor welding practices. 304 stainless needs to be back purged properly otherwise the weld is compromised. It is also more sensitive to heat than mild steel. If too much heat is put into the material during welding, chromium will precipitate out of the weld leaving a brittle area within the heat effected zone that is prone to corrosion and stress cracking. This is a good reason why true high quality race headers will use 321 stainless and not 304, though if a car isn't going to see the track or repeated dyno pulls 304 is usually fine. This is also why we chose 1020 mild steel for our basic headers. No MIG work on these bad boys, any header we complete will feature TIG welds.

It is likely that our catless systems will include a flex in the exhaust where the cat used to be. Because of the design of the stock replacement headers, we would have to include a bellow in each primary, which we could do for the cost of the bellows. That said, replacing worn out flex's is no fun either, something to consider.
Nice seems like you got this all figured out. Can't wait to see the finish product.
 

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Discussion Starter · #11 ·
All welded and ready for testing. Here's some shots of the Jig and the finished product. Sound clips coming soon ;)









Happy New Year!
 

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Excited to see some progress! I will be a potential customer. Right now I have a custom uel single port header made by infernofab which I am very happy with. There is really only one drawback to his header for me. Because of the uel design and size of the collector, this section tends to hang down lower than anything else on the motor, limiting my clearance. Since I am lowered quite a bit and would like to go lower, this poses a problem for me.

I am interested in seeing how your product turns out, especially if it retains the same clearance of the stock piece. My ej22 is also boosted so I was considering going to an EL design to muster a bit more power out and change up the sound.

I'll definitely be checking in, and I would love to hear a sound clip of each! :D
 

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Discussion Starter · #14 ·
Tomorrow morning we will be test fitting our prototype. Should have sound clips up tomorrow evening comparing an all stock exhaust vs. our header on the stock system. In the near future I'll be purchasing a Magnaflow to really show off the new sound. Great to hear that people are interested in our header!
 

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GF OBS-T, GM RS EJ20, SF EJ20
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Maybe a set of these can help improve the 12.89s 1/4 mile of my single port EJ222...

Do you think these can support an uppipe/turbo like the oem y pipe can?
 

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Discussion Starter · #18 ·
Hi guys,

Sorry for the lack of updates, would like to let everyone know we're still alive, though the business is on hold at the moment. Mid January my university professors decided to go on strike and it lasted 3 weeks, providing only 2 months to do 3 months worth of engineering classes. The university machine shop closed down for half of that. I am the team leader for our Formula SAE team, and we have to complete the car by the end of April at the very latest. Our school has never had a working FSAE car before, and our team has only a handful of contributing members most without much manufacturing experience. Losing weeks in the shop threw us far behind schedule. In light of this, headers will be postponed till June. We don't want to get into a situation where we took orders but couldn't deliver you your product in a timely manner.

Now for the good news! Install went flawlessly, headers slipped right on no hassles. Because of the stock axle back and cats, the sound levels aren't that much different than stock in most conditions. That being said there is a very noticeable difference in exhaust tone. Even at idle the 'rumble' can be heard behind the car. The few inches of primary length difference seem to change the tone more than we expected. When you get on the throttle this thing sounds great!

In terms of power there's a very noticeable difference. The engine doesn't seem to struggle as much when up shifting early. Power comes on strong and smooth right up to redline without the uneven hesitation of the stock system or lugging in low rev's or the fall off at 5k rpm. Throttle response has increased as well. Throttle input is much more precise; rpm's are sensitive smaller pedal movements than with the stock header. Overall, it feels there are power increases right across the board. Even the girlfriend noticed.

Drivability has improved more then we expected in little ways you wouldn't normally think about. Because the header flows so much better than the stock piece, engine braking has decreased a LOT. This is a good thing because for one it makes for more seamless downshifts and two; it allows you to coast off throttle longer in higher gears giving you better fuel economy. After some measurements, it appears ground clearance is about a quarter inch less than stock, though we have plenty of room to make the clearance more than stock for the production run as there is plenty of room to play with.

All in all, we consider the prototype a big success. So far it has 5000 km of hard city driving on it with nothing but smiles. The improvement is impressive especially considering the rest of the exhaust is completely factory.
 

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2000 Impreza OBS
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Happy to hear an update, was just talking to a friend of mine about his uel and he asked why I didn't have one yet and I said none were available... Yet. How ironic there's an update today.

Sent from my SCH-I535 using Tapatalk
 
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