Exhaust design

[lamcote]

I think that may be just a description of the Zero manifold itself?

See the pic in this thread:

 m http://www.mr2roc.org/phpBB3/viewtopic.php?f=7&p=355502 m

[Bernie]

Yes that's the Zero description

I'm away till Sunday in the files Rob gave me are all previous dyno's as he progressed the build I'll post them here for reference


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[shnazzle]

That's a pic of the SP de-cat pipe... With cat hehe.

I just don't get the description of the manifold. Was it changed? Was the collector modified for better/different flow?

The 171 from Bernie does seem largely dependent on the Apexi. Don't see those kinds of gains happening with my emanage blue.

I think this is on topic; let's say I add a 200cell and PPE. What would I most likely need to change in my map to make sure I make no losses and get some gains?
Both timing and fueling?
I guess if the exhaust system causes more air to come in through the intake valves, I can add more fuel.
Seeing how stg1 cams aren't appreciated by PPE. I guess changes in timing wouldn't be welcome either

[lamcote]

Yes, he had a cat welded into the decat pipe apparently, not a bad idea.

I really think it was just a standard Zero manifold and a standard decat pipe, other than adding the cat in the middle of course.

Regarding the map, I think you could really only get it done on a rolling road, but ignition timing changes shouldn't be a problem.

[lamcote]

This seems to be what we are looking to replicate. Shame it wouldn't fit, would it?

 m https://www.eliseparts.com/products/sho ... -manifold/ m

[Bernie]

From the Archives  :-) :-) :-)

 l viewtopic.php?f=7&t=30005&p=367763#p367763 l


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[shnazzle]

This seems to be what we are looking to replicate. Shame it wouldn't fit, would it?

 m https://www.eliseparts.com/products/sho ... -manifold/ m

Oooohh I like that! That is quite sexy.
Sure it doesn't fit? Looks to go quite low. Possibly clear subframe ?

[lamcote]

I did wonder whether it might just fit....

[manos3003]

It won't fit chaps. Don't think you can squeeze a cat pipe and a backbox along with this without clashing.

I'm working on something, but the actual swap is keeping me busy  s:D s:D

I'll let you know how it goes as soon as I've made some progress with CFD (yes, you did read right, there'll be science in this bad boy)   s:lol: :lol: s:lol:

[ChrisGB]

It won't fit chaps. Don't think you can squeeze a cat pipe and a backbox along with this without clashing.

I'm working on something, but the actual swap is keeping me busy  s:D s:D

I'll let you know how it goes as soon as I've made some progress with CFD (yes, you did read right, there'll be science in this bad boy)   s:lol: :lol: s:lol:

Will the CFD package be able to model the scavenging pulse timings? Good flow is one thing, but to achieve the highest VE, you need the tuned lengths for maximum scavenging and pulse tuning.

[manos3003]

I'll do some calculations on harmonics to see. They should give me optimum primary length. CFD is mostly to ensure smooth flow, with minimal obstructions, thus less pressure drop without reason.

It won't fit chaps. Don't think you can squeeze a cat pipe and a backbox along with this without clashing.

I'm working on something, but the actual swap is keeping me busy  s:D s:D

I'll let you know how it goes as soon as I've made some progress with CFD (yes, you did read right, there'll be science in this bad boy)   s:lol: :lol: s:lol:

Will the CFD package be able to model the scavenging pulse timings? Good flow is one thing, but to achieve the highest VE, you need the tuned lengths for maximum scavenging and pulse tuning.

[lamcote]

Yes I did that, my calculation came out at around 40 inches which is really not feasible on our car. Be interested to see what you come up with?

[shnazzle]

On a separate note; I inquired about the cost of a custom full exhaust design and we'd be talking almost 400 for the cat pipe, 550-600 for the manifold and another 450 for the back box (the latter ranging from 350 to 600).

So, with all the best will and intentions, spending near 2k on an exhaust is a bit silly to extract what might be 10-15hp.
Not when another 2.5k gets your another 100 hp from a turbo

[lamcote]

But do you really want a turbo?

[shnazzle]

No haha
I could swing a supercharger though I think.

Point was more that you're better off with buying one. I think my personal preference would prob be zero and custom cat pipe with 200 cell and better back box

[Carolyn]

If I were to do a supercharger job for a customer, I'd have to charge £3000 to £3,500 to make it worth my while... No don't ask!  I'm not about to go into the supercharger conversion business.

Doing it for myself, it has cost just about £1,000 including 200 cell cat, all stainless exhaust parts and stainless performance back-box, engine management and all components.

I just can't see spending  thousands to get a few BHP on a car that is only worth £2 - 3,000 when it's done.

Two grand plus to get 15 hp max with a very very expensive exhaust??   I agree with Schnazzle, go turbo, go 2ZZ go for obvious big lumps of BHP rather than engineering the very marginal gains.  Marginal gains are for when you're restricted by a rule book, and they are very expensive. (See F1).

The advantage of the supercharger is you can get any HP increase you want (within reason) by pulley sizing and engine management.  Much more than 190 bhp out of a 1zz is going beyond the engine's design for reliability.

[shnazzle]

I can't lie though. Money aside, I'd be all over stg1 or 2 cams, custom tuned exhaust, ported heads and throttle body and standalone ecu.
I'd be very very happy with 180ish hp on a "stock" 1zz. Id keep all the great characteristics of the 1zz while having a very noticeable increase in power.

Supercharger is very very attractive though and exhaust is a fair bit easier.... Bigger  s:) s:)

[manos3003]

Expanding on what Patrick and Carolyn said above, the answer to this is "That's the beauty of ENGINEERING. Formulas and math mean nothing if the end result is unrealistic, but if you have constraints you see what you need to do to work around them"  s;) s;)

If I have to sacrifice length, I'll still do some calcs to make sure the math stick. I want to make sure if fits in the CAD first before I make it.

Once I dyno test it, I'll post results and designs too.

Yes I did that, my calculation came out at around 40 inches which is really not feasible on our car. Be interested to see what you come up with?

[lamcote]

Sounds good, I look forward to seeing what you can achieve, keep us posted?

[manos3003]

Of course  s:) s:)  Once my 2zz swap is complete, this project will receive my full, undivided attention   s:D s:D  

Sounds good, I look forward to seeing what you can achieve, keep us posted?

[ChrisGB]

Yes I did that, my calculation came out at around 40 inches which is really not feasible on our car. Be interested to see what you come up with?

I'm coming up with 26" for maximum power or 38" for peak torque based on an exhaust valve opening 42 Deg BBDC and a 3" collector using A. Graham Bell's formula. You could possibly tweak the pipe diameters to move the peaks a little.

[ChrisGB]

I can't lie though. Money aside, I'd be all over stg1 or 2 cams, custom tuned exhaust, ported heads and throttle body and standalone ecu.
I'd be very very happy with 180ish hp on a "stock" 1zz. Id keep all the great characteristics of the 1zz while having a very noticeable increase in power.

Supercharger is very very attractive though and exhaust is a fair bit easier.... Bigger  s:) s:)

The big problem with the 1zz is it is a long stroke engine, so the head and consequently the valves are small in comparison to the cylinder volume. This makes extracting big power difficult. SJ Spitz built a cracking NA setup with 1.93L sleeves / pistons, stage 2 cams and a very high (11.5:1 IIRC) compression ratio that made somewhere close to 200bhp. There is no substitute for cubes it seems  s:wink: :wink: s:wink:

[lamcote]

I know what you are saying about the stroke length and valves, but if he managed to get 200bhp from a 1.93l engine, that suggests the valves aren't actually all that restrictive, particularly in a standard capacity engine?

[M.R.]

I know what you are saying about the stroke length and valves, but if he managed to get 200bhp from a 1.93l engine, that suggests the valves aren't actually all that restrictive, particularly in a standard capacity engine?

Valves are so close to cylinder walls that it limits flow. This is just hearsay, so don´t quote me on this... So it could be that hp increase comes mainly from added flow of better cylinder/valve clearance?

[manos3003]

Actually, neither of you are wrong. Depends which formulas you use you either calculate total exhaust length or purely primaries.

Now, stop distracting me from my engine swap and I'll crack on with this during the summer  s:D s:D

Yes I did that, my calculation came out at around 40 inches which is really not feasible on our car. Be interested to see what you come up with?

I'm coming up with 26" for maximum power or 38" for peak torque based on an exhaust valve opening 42 Deg BBDC and a 3" collector using A. Graham Bell's formula. You could possibly tweak the pipe diameters to move the peaks a little.