37 replies to this topic

[gravelRX]

I have an extra EA82T with no internals and a crossmember from another turbo car. I assembled it on the engine stand including the parts that will effect clearance on the header/uppipe when it is installed.

Need to secure the turbo to the engine so when I cut the pipe away and leave only the flanges the turbo won't move and effect placement when I weld it all together.

Still thinking on the fabrication.
Need the formula for equal length headers vs chamber CC's vs pulsewidth vs pipe diameter vs compression ratio, blah blah..need to get in my library and find that article/chapter again.

Haven't gotten too far along with this project but will update if anyone shows interest.


Extra greasy! Need to completely attach the motor mounts. Coolant lines, oil lines, check power steering lines on the RX to see if they are going to be in the way. Have alot to do before I start welding.







Constructive input and ideas would be much appreciated.
When I was doing the FMIC some of you guys helped more than you realize with your input.

Wish me Luck,

Jay

[[HTi]Johnson]

Nice, so you're gunna make a custom up pipe? So any ideas on how you're gunna do it. and how wide is it gunna be. I was told, the wider the laggier, but better top end.

[gravelRX]

I'm planning on using 1 3/4" piping because I have about 20' of it left from the FMIC fab.

I don't want to go too big because I still want the bottom end. I might change a bit when I find my math.


Jay

[subyrally]

i would suggest that yourun two seperat pipes to a collector just before the turbo. that might just be mylikings though, im not a big fan of the stock style manifold, its not hte best design for flow.

[gravelRX]

Oh yeah. Going to mimic the equal length headers I've seen others make in the past. TWE and a few on the BYB. Not too many ways to build them equal length or close considering the space limitations.
I'm sure someone will bark out that I'm copying a TWE header or something of that nature.
Imitation is the sincerest form of flattery I say.

I'm not one to drop 400.00 into a set of headers either.

Still looking for the math to find out what is optimum size pipe dia. and length.

Working on the engine jig now.

Jay

[subyrally]

instead of equal length, try tuned length. the way thesse engines arelayed out, its easier to go tuned instead of equal. tuned is where one side is twice the length of the other, but it evens out the pressure like equal, just sounds better. that and you would have to make fewer bends. look at the borla headers for the ej22, its only a two pipe header, but its the same design as what im talking about. another ting you could di is to make a removable uppipe so that you wont have to make a new header or chop the new one if you decide to change turbos.

[Myxalplyx]

I could see why you would imitate the TWE header. It's already been done and you know it works. I would think that it is pretty much equal length based on the sound alone. My car sounds nothing like anything 'boxer' like the Borla header does for the 2.5RS or even the WRXs. The sound is raspy, almost motorcycle like. My wife says it sounds like a motorcycle is coming down the street when I pull up. Maybe I should do some sound bytes so you know what I'm talking about.

Here is a picture to help you get started.


If you look close enough, you can tell it is not exactly equal length. It gets the job done though. Perhaps a tuned length header is possible if the drivers side exhaust pipe does not go towards the back but rather the front. I dunno. Space is tight either way. Good luck!

[gravelRX]

Haven't cracked a book yet. Just had to pull the pizza guy from the edge of the new driveway. he ripped a big chuck of new asphalt loose. Yay.

Suby, thanks for the tip about the tuned vs equal. I will look for a good picture of the EJ header.

Myx, I do want mine to sound like a boxer, but it's not that important. Special thanks for the picture and the advice.

Built the majority of the jig to hold the turbo in place when I cut the exhaust pipes off the flanges. Chunks of scrap steel and some quick welds. Need to put the 45's in and call it done for tonight.



It would be bad to go through all this trouble and build something that won't fit on the RX because the turbo mount sagged when I was fabbing it up.

Shadow- Couple Q's from your post.

*Centerline measurements- on that.
*Step from head into pipe- That's going to come from using the original flanges. Might even have to open them up a bit.
*Burns 2-1- I'm not following you on this one.
*Slipjoints- I'm going to weld it in and see what happens. Don't want to have any of the piping crack but doing it with the grassroots frame of mind.
The downpipe has been in for a year and hasn't failed as of yet. It's solid from the turbo out to the back.

Have thoughts on the 1 3/4" piping and how it will effect boost onset?

Appreciate all the other advice. I'm probably going to find pictures of some good designs and measure as best I can then go to welding.


Regards,

Jay

[Vanislru]

I'm planning on using 1 3/4" piping because I have about 20' of it left from the FMIC fab.

I don't want to go too big because I still want the bottom end. I might change a bit when I find my math.


Jay

Jay,
1.75" is that ID?
I'm going to fab. a header up for a turbo gl-10 4x4 coupe, I already have 2 TWE header/dp's on my wagon's. I can't remember the I.D. of the header but it's too big IMO. Top ends great and all but I'd rather get the top end from a larger turbo [like my tdo4] not from oversize header pipes. 1 3/4" sounds too big to me, I'm going to see if I can find some 1.25" ID tubing for my header and use my twe pipes as a guide for the design.
Just a thought.

BTW your FMIC looks awesome.

[gravelRX]

Measured the factory exhaust tonight. 1.75 out of the head, both sides, to 1.50 at the base of the turbo. I searched for TWE specifications for the OD/ID and couldn't find it.
MY piping for this project is 2.75 O.D.

I don't much care about top end, I'm looking for power in the bottom, mid range.

Anyone running the TWE header with a 260* Delta cam? When does that come into the boost? Mine starts at around 2650 and pull right up until redline. Factory boost. I would like to keep it there or get a bit lower, say 2500. Top end does not matter to me.

So a big cam in a naturally aspirated, slightly overcarburated, lightened flywheel, strong clutch, rear wheel drive, sub 2600 lb, 245/50 15 shod car would get me what I want. And the instantanious throttle response would be nice too.
A Miata with a built 5.0 out of a Mustang would probably fit the bill. Rear from a Thunderbird. Anyone want to buy an RX? I'll finish the header before you pick it up.

Tomorrow is another day and I won't order pizza.(See previous post)

Jay

[NorthWet]

Measured the factory exhaust tonight. 1.75 out of the head, both sides, to 1.50 at the base of the turbo. I searched for TWE specifications for the OD/ID and couldn't find it.
MY piping for this project is 2.75 O.D.

How did you measure the pipe? The heat shielding makes it look much bigger than it is. And there is a MAJOR neckdown at the turn up towards the turbo. (I believe that it was rallyruss that discussed the actual pipe sizes, and how narrow that neckdown was.)

[WJM]

I would have more info on the cams...as I did run them in my wagon with the header. I did not tune it in...but it pulled to 7500.

[gravelRX]

Measured with the exhaust off the engine, across all three openings of exhaust.

Spent a little time today with a cut-off wheel getting the heat shields away from the factory pipe. I was surprised to learn they have cloth material in them for insulation.
I don't remember the 87 having it. this pipe is from an 88.

I'll search for a rallyruss post on TWE.

Thanks,

Jay

[WJM]

Mid range and low end eh?

Keep the stock turbo and port/polish the exhaust side.

TWE header design. It DOES NOT LAG ANY MORE THAN THE STOCKER. If anything its WAY better then the stocker down low. Midrange is 11ty billion times better. Top end too.

Make a proper downpipe. :-p

you've seen my numbers...100+hp/130+tq at the wheels on stock boost.

165/220 or so on 15 PSI with an STi TMIC...

[WJM]

oh and you might want to have the weight of the engine and such ON the crossmember instead of the crossmember stretching the engine mounts down....that way you can properly clearance the header from engine/crossmember.

[gravelRX]

Do you recall OD/ID on the TWE? You don't like my solid DP? Whatsamattawifyou! Itsaperty!

Read the whole post about the motor mounts. Might get a ratchet strap and cinch the motor and crossmember together for fitment sake. I'll eventually get under the RX and see if I missed anything else that might get in the way.


Jay

[avatar382]

Measured the factory exhaust tonight. 1.75 out of the head, both sides, to 1.50 at the base of the turbo. I searched for TWE specifications for the OD/ID and couldn't find it.
MY piping for this project is 2.75 O.D.

I don't much care about top end, I'm looking for power in the bottom, mid range.

Anyone running the TWE header with a 260* Delta cam? When does that come into the boost? Mine starts at around 2650 and pull right up until redline. Factory boost. I would like to keep it there or get a bit lower, say 2500. Top end does not matter to me.

So a big cam in a naturally aspirated, slightly overcarburated, lightened flywheel, strong clutch, rear wheel drive, sub 2600 lb, 245/50 15 shod car would get me what I want. And the instantanious throttle response would be nice too.
A Miata with a built 5.0 out of a Mustang would probably fit the bill. Rear from a Thunderbird. Anyone want to buy an RX? I'll finish the header before you pick it up.

Tomorrow is another day and I won't order pizza.(See previous post)

Jay

I've got the 260 cams with the TWE header. Comes on full boost at hits hard right around 26-2700. However, in first gear it gets up there really, really fast. Redlines almost instantly, then, when you shift, it's right in the powerband

[NorthWet]

I would have more info on the cams...as I did run them in my wagon with the header. I did not tune it in...but it pulled to 7500.

* Mini 'jack: Pulled to 7500 without any obvious valve float? Was this with stock valve springs, etc? Just something I have been wondering about... End hijack *

[nkx]

http://stores.ebay.com/VertexNow

these guys are out of delaware. lots of supplies for custom intake and exhaust projects.

[WJM]

* Mini 'jack: Pulled to 7500 without any obvious valve float? Was this with stock valve springs, etc? Just something I have been wondering about... End hijack *

pulled to 7500 with out any signs of dropping off in power...thats just where I shifted at.

[gravelRX]

Ave, That's what I want to hear. First gear in mine is like that too. Especially in L range.
WJM, just because it will rev to 7500 doesn't mean you should. Remind me never to let you drive my car. It would shock the old girl to be beaten on that hard.
Jay

[WJM]

Ave, That's what I want to hear. First gear in mine is like that too. Especially in L range.
WJM, just because it will rev to 7500 doesn't mean you should. Remind me never to let you drive my car. It would shock the old girl to be beaten on that hard.
Jay

The only ones that went to 7500 was my wagon and the first RX i had. Wagon went to 7500 just once. The RX 3 times. Otherwise, I always shifted at 6k with the cams. 5500 with stock cams.

I dont abuse my cars.

[avatar382]

These engines will rev to 7500 eh? Interesting..

The once or twice I was around 7 grand I got scared and shifted. Maybe I should take it up to 7.5K one of these days to see if there is any powar up there...