Equal or unequal headers???

[StrokedEJ]

Just want to know the pros an cons as thinking of getting another set. And recommended brands?

 

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[Guest]

Ssi unequal work well.

[StrokedEJ]

Sweet wats the pros an cons an where can i buy? In nz

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Ssi unequal work well.

Sweet whats the pros an cons?

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[pedro]

Equal length = no Subaru rumble..Con..

Lighter and ultimately more efficient..Pro..

[StrokedEJ]

Equal length = no Subaru rumble..Con..
Lighter and ultimately more efficient..Pro..

Ok other than the loss of rumble there is no other benefits?

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[Sako]

I think they run quite close to some critical plastic parts underneath like the bottom tank of the radiator and can be hot so that needs to be considered.

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[pedro]

15 minutes ago, StrokedEJ said:

Ok other than the loss of rumble there is no other benefits?

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Oem headers won't limit you until over 280 wkw ish..

Equal length best for max power..

Unequal length cheaper to make so should retail for less..

[StrokedEJ]

Oem headers won't limit you until over 280 wkw ish..

Yeah thats why i want to change. Ive had untuned ,semi tuned an tuned or equal before but tbh could not find any difference besides the sound of car. Hence this question if anyone knows any thing

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[Guest]

The design of the header and collector can play a bigger part than the whole tuned etc debate.

 

http://www.clubsub.org.nz/forum/index.php?/topic/50300-stock-headers-vs-ssi-style-headers/

 

[StrokedEJ]

The design of the header and collector can play a bigger part than the whole tuned etc debate.

Ok so you rekon 4-1 or 4-2-1? Not really sure but want to do abit of homework on this build

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[YoungOne]

Interesting post by Steve Murch on his facebook page regarding header diameter and length: 

 

"Turbo’s require velocity to function the more the better thus comes the two stroke effect, we increase header size or length we can move the power band further up a lot of the time for minimal gain but a great loss of power band, anyone who has rode a 125 MX bike knows what in talking about.
So my approach is to keep gas speed up as much as possible to the turbine wheel which can be the speed of sound and more but just as important the low pressure wave that returns into the chamber, we use this to help pull the next charge into the combustion chamber before the next power stroke this when done right can make a four stroke turbo engine over 100% efficient.

There’s a few formulas out there of use eg: header pipe length as P = ((850 * ED)/rpm)-3 where ED + 180 degrees plus the number of degrees the exhaust valve opens before BDC and rpm is the engine speed.
I use my own version of this more suited to turbo setups but one thing that’s harder to calculate is header area or dia, you can have long small and short fat to achieve the same thing to which often as we all know headers are made more for fitment not necessarily ideal performance then we have stepped headers for a staged power band as in two different pipes Dia in one runner.

Best example to understand what effects things can have is comparing two engines of similar displacement, 4G63 and EJ20.

Due to engine lay out the 4G63 is inline versus a flat 4 EJ20, using a GT35R .86 A/R turbine we would on the average generic headers see full boost around say 4500 on the 4G and closer to 5500 or more on a EJ the main reason is area/length.

The EJ would have close to 3x the header length of a 4G and having less exhaust port flow compared to the 4G makes for a doomed setup, here’s the killer EJ owners now buy larger than stock dia headers along with larger dia up pipe equals slower exhaust gas flow for what maybe a marginal gain up top and very poor spread of a power.

Using a basic formula of area it’s easy to see where it all goes wrong eg: primary headers on the 4G ID of 38mm and 450mm long gives a area of 1134mm x 450 = 510417mm. Applying the same to the EJ but longer headers 38mm x 1200 = 1360800mm that’s 2.6x bigger than the 4G, can you see the issue?
Now let’s change things a little lets go to so called big runner headers 41mm ID on the sub but retain the length we now get 1584510mm in area or 1.16x larger making them 3.1x bigger than the 4G headers, we only changed the ID by 3mm. This doesn’t include the effect of the up pipe in area.
Bottom line you now have to work the engine so much harder to make boost generate heat etc now for some when using launch control, NOS or flat shift it’s not a issue right? But was the gain worth the loss of a better power band with marginal gain in peak torque ? In fact at times you loss peak torque, if you search the net you’ll find most 4 strokes reach peak torque between 5-6000rpm very few will hang on further.

My idea for any given turbo car is maximize the power band but more so the torque after all that’s what makes your car get to point B faster thus turn the hair dryer on faster, or as I like to call it a really powerful turbo car that acts like a NA….not a bad thing.

There is much more to this as in head flow, cam specs, intake design ,comp ratio,fuel, turbo sensitivity ( how much load it can take before serge ) on that note when dealing with little motors as a 2ltr you could see 20psi at 2000 rpm but things can go wrong. You end up with too lower rpm and load to high causing detonation plus other tuning issues and driving the turbo to the point of hurting it and the motor,2ltr is still a small motor thus turning a large turbo doesn’t make it user friendly there’s no substitute for displacement.
Another point to note is the collector used on turbo headers, large collectors kill exhaust flow as in losing velocity I like to terminate the merged primaries right at the face of the turbo flange that keeps exhaust flow up right at the turbine, much better than killing exhaust flow in large runner headers to be collected in the turbine housing then try and accelerate them. Equal length? Yea na plus or minus 25mm per runner works fine but pulse tuning based on firing order on a split pulse housing is a must as per how the gate is mounted all affect the threshold point.

The sweet spot for peak flow in a turbine housing is around the point the AR is calculated which depending on turbo frame size around 20-40mm in from the turbine housing mounting face not at the end of the headers, if you have a dead turbo have a play with a air gun blowing into the turbine ports you’ll see what in meaning.

Rounding this pointless post take note of the picture from early 80’s F1 turbo headers I’ve attached, small runners somewhat short with a large turbine housing 1500cc 1400hp 70psi plus in qualifying mode back pressure often less then 1/1. 

Hope some of this makes sense or tiny bit of help downside for me is customers come to me with a already built motor which makes life hard to get the ideal result without re engineering their engine, I have at times done setups with a cam split of [email protected] intake and [email protected] exhaust works awesome but more to why that is another time."

 

Original Link:

 

https://www.facebook.com/permalink.php?story_fbid=10154608738582680&id=255636937679

[Guest]

Holsets require a different approach to headers than say a garrett. Hence why murch likes to spec the build. 

 

If you want something off the shelf that doesn't cost moonbeams the ssi unequal are the way to go. Trade me or nzkw.

[Username]

45 minutes ago, evowrx said:

Holsets require a different approach to headers than say a garrett. Hence why murch likes to spec the build. 

 

If you want something off the shelf that doesn't cost moonbeams the ssi unequal are the way to go. Trade me or nzkw.

Clint, has Murch actually built an ej20 for someone yet where he has got them to build to his specs for the  heads, headers, up pipe, down pipe, turbo etc?

 

Is there proof the holset setup significantly improves response, power etc on say a comparable Garrett twin scroll setup where off the shelf parts are used? Or is he still waiting for a Guinea pig to test his theory's on? 

Edited August 29, 2017 by Username

[Guest]

5 minutes ago, Username said:

Clint, has Murch actually built an ej20 for someone yet where he has got them to build to his specs for the  heads, headers, up pipe, down pipe, turbo etc?

 

Is there proof the holset setup significantly improves response, power etc on say a comparable Garrett twin scroll setup where off the shelf parts are used? Or is he still waiting for a Guinea pig to test his theory's on? 

 

I was meaning in a general sense not EJ specific. I don't know you would have to ask Steve. I know there's not many but it's not an easy feat fitting one to a sub compared to garrett stuff.

 

Don't see many twin scroll garrett builds eithet which makes it hard to compare on both fronts. In the states its generally been gt40 or 42 size stuff in a t4 footprint and often with added displacement.

 

I personally think you need a 2.5 or larger to offset the lower efficiency on a sub but I dont have evidence to back it up.

 

The difference with my 2 vs 2.5 was night and day as far as response goes.

[Username]

This is the problem, I was going to get him to do my setup but his theory's on ej20 have not been tested and considering I was quoted 3000 dollars plus gst  just for the headers ( a lot of fabricators don't want to know) you can imagine how much a complete setup designed by him would be. 

 

It's  a big risk, when Plenty have bolted a gtx35r onto a built motor and your good for 450wkw+ depending on boost level, maybe laggy but there's ways around that.  

 

A gt40 on even 2.5 would be laggy as S*** wouldn't it! 

Edited August 29, 2017 by Username

[Guest]

@rex-leggy was 2.35 with an hx3540 or hx40 iirc and that was epic. @gotasuby would have details but curve was insane and made massive power before lifting heads around 6k iirc.

[StrokedEJ]

This is the problem, I was going to get him to do my setup but his theory's on ej20 have not been tested and considering I was quoted 3000 dollars plus gst  just for the headers ( a lot of fabricators don't want to know) you can imagine how much a complete setup designed by him would be. 
 
It's  a big risk, when Plenty have bolted a gtx35r onto a built motor and your good for 450wkw+ depending on boost level, maybe laggy but there's ways around that.  

3k damn thats alot considering most fabricators charge average of 1200ish

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[mention=136]rex-leggy[/mention] was 2.35 with an hx3540 or hx40 iirc and that was epic. [mention=186]gotasuby[/mention] would have details but curve was insane and made massive power before lifting heads around 6k iirc.

What head studs was he using when head lifted

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[Username]

2 minutes ago, StrokedEJ said:

3k damn thats alot considering most fabricators charge average of 1200ish

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What head studs was he using when head lifted

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It's 3k because it's complete twin scroll setup with up pipe part of the cost. 

 

Head studs probably should be 14mm stud conversion you would think, arp2000 wouldn't cut it. The dtech 500kw car build in last months nzperformance used arp625 which are supposed to be close to 14mm stud conversion capability without the hassle of machining the heads etc. it's the way I'm going. 

[StrokedEJ]

It's 3k because it's complete twin scroll setup with up pipe part of the cost. 

 

Ssi do twin scroll Head studs probably should be 14mm stud conversion you would think, arp2000 wouldn't cut it. The dtech 500kw car build in last months nzperformance used arp625 which are supposed to be close to 14mm stud conversion capability without the hassle of machining the heads etc. it's the way I'm going. 

Yeah custom aged is the way i think too. Just got my set last week. 3x the price of arp2000 tho

 

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[Guest]

End of the day with your setup @Username I wouldn't bother switching it all out as discussed its an epic amount of coin for a possibly low return.

 

 

[Username]

Just now, evowrx said:

End of the day with your setup @Username I wouldn't bother switching it all out as discussed its an epic amount of coin for a possibly low return.

 

 

Yep I agree which is why I didn't.

 

I pick the engine up Thursday too, so this weekend will be fun putting it back in the car.