H&S Manifold

[markiii]

Guys,

I was talking with Ian at H&S and he mentioned that they are now in a position to offer a replacement no precat manifold




A one off price will be £475, A group buy of 5 + the price will be £425.
 
All prices are exclusive of fitting/delivery and VAT.

I'm concious that this is significanlty more expensive than teh che Manifold.

Personally I'd pay a littel more for the benefit of getting it from the UK, and I would expect superior workmanship. However the questions is how much more you guys would be prepared to pay?

Ian has suggested that there could be some flwexibility depending on interest, so I'll cast it over to you guys.

would you pay more than teh che price for an H&S?  what would you pay?

[Two's Company]

Would this add any more power/ torque? If so, roughly how much?

[markiii]

good question, I don't know of anyo9nes who has dynoed a replacement header only.

but  there are gains just from removing teh precats so I would expect gains fo some higher order from removing and smoothing airflow

[Anonymous]

That does look very nice.
As I see it with regards to non-stock manifolds you have 4 options:

1/Gut the pre cats in stock manifold - cheap but a pain.
2/ Get a che manifold - No hastle with knocking out cat material but all the hastle of getting the gear over from the US.
3/Get a PPE/TRD Header - Good bits of kit but you pay for it

4/ Go for something like this.

This for me would fill the gap between what I really want (TRD header) and what I can realistically afford (£400 ish). I would pay the extra for this over che's as it's UK and from a company with a proven track record of quality tube work.

In short I'd be provisionally interested

[Two's Company]

Maybe H&S would consider asking Ruston if they could dyno his car to see if there has been any improvement.  I'm sure more people (me included) would be more inclined to buy the manifold if there was a proven 'x' amount of power/torque increase.   s:? :? s:?

[markiii]

Maybe H&S would consider asking Ruston if they could dyno his car to see if there has been any improvement.  I'm sure more people (me included) would be more inclined to buy the manifold if there was a proven 'x' amount of power/torque increase.   s:? :? s:?

Seeing as how he has their backbox as well I'mnot sure how much help that would be.

[Anonymous]

Gutting the pre-cats isn't that much of a pain. With all these solutions you are removing the exhaust manifold. The gutting is only a 10 minute job.

If I was re-modding a standard car I think I'd just gut the pre-cats knowing what I know now   s:? :? s:?

[Anonymous]

Looks a lovely piece of kit, it also has space for two o2 sensors so theres no need to mess with wiring like the ppe system (not that that takes long though)

[Anonymous]

Gutting the pre-cats isn't that much of a pain. With all these solutions you are removing the exhaust manifold. The gutting is only a 10 minute job.

If I was re-modding a standard car I think I'd just gut the pre-cats knowing what I know now   s:? :? s:?

I've not gutted my precats but I'm assuming there  must be a lip of metal or something in there for them to mount onto. Even if you remove the cat material you are still going to have this creating turbulance. Besides the H&S effort looks a little more free flowing then the stock item.
You are right though gutting precats prob under £20 so you are saving over £400.

[Anonymous]

Bumpity Bump.

If anyone else is interested in this I don't mind liasing with H&S to sort out a GB.

let me know

[mg]

ooooo, shiny!

Question: why do the pipes group in 1/4 and 2/3 pairs?

[Anonymous]

Hmmm - I just thought it made it look nice!

I've just seen the stock manifold after taking off my heatshield - God it's ugly!

Iwould assume the 1/4 2/3 setup is something to do with airflow.

Want one?

[markiii]

look where the 02 sensors are and comare to the stock one

the engine ecu is ecpecting an 02 to read from a given set of cylinders

[mg]

look where the 02 sensors are and comare to the stock one

the engine ecu is ecpecting an 02 to read from a given set of cylinders

That will be it.  I can't see how it would be airflow as the shorter and straighter, the better.  Well, maybe to make them all the same length.   Would need a bit of CFD to test.

[Anonymous]

would you pay more than the che price for an H&S?  what would you pay?

Can you answer a couple of questions for me:

1. Will the manifold have the lower mounting bracket fitted or does it just hang free?
2. As this been fitted to a car yet, the reason I ask is the positioning of the O2 sensor on the right as you are looking at the manifold could be an issue, my lead is very tight at the moment and this looks lower.
3. Could the manifold be ceramic coated, heat being the main problem.

The reason I'm asking is due to the problems I've had with the Che, currently I'm running without the heat shields due to the threads stripping on one of the brackets, they kept coming lose and rattling. I've removed all brackets, which does improve the look but the price is extra heat.

To answer your question then yes I would pay more, after my Che experience, "you pay's your money and take's your chance"

I would like to pay between £450 - £480 including VAT. Plus the coating cost if available.

[peppyuk]

What length are the pipes?
How much lighter than stock?

I'm assuming there equal length at this price.

[Anonymous]

Can you answer a couple of questions for me:

1. Will the manifold have the lower mounting bracket fitted or does it just hang free?
2. As this been fitted to a car yet, the reason I ask is the positioning of the O2 sensor on the right as you are looking at the manifold could be an issue, my lead is very tight at the moment and this looks lower.
3. Could the manifold be ceramic coated, heat being the main problem.

1. Mine has a lower mounting bracket fitted, fabricated by H&S when they fitted the manifold.
2. Yes, me see http://www.mr2roc.org/phpBB2/viewtopic.php?t=12571 The lead to the O2 sensor needed to be extended. Again this was done by H&S as part of the fitting.
3. Don't see why not. Mine isn't and it does get hot under the bonnet. However, this doesn't seem to cause any problems even in hot weather.

Overall this is a very nice manifold. It is not cheap but is very good quality.

[Anonymous]

Thanks for your quick answer, the problem I'm having with the heat is with my Tein suspension, the top motor mounting (EDFC) on the drivers side is getting very hot  s:shock: :shock: s:shock:

That's one thing I most interested in is the quality, I think I've paid the price a bit using the che, but it did the most important thing - got rid of those dam pre-cats  s:lol: :lol: s:lol:    s:wink: :wink: s:wink:  

Thanks again.
Rob.

[Anonymous]

Certainly looks an excellent piece of kit but I fitted the che a couple of months ago (excellent price and service - guess which took longer to arrive, the header from the US or the new stock manifold gasket from Mr T in the UK??)

I'd like to see the finish on the manifold to head joint side - with both the stock and the che there is a gap between the manifold flange and the pipe which I think could cause a lot of turbulance. If i'd have had the time I think it would have been worth using a grinder to smooth the transition. If the new bit of kit attends to this sort of detail then I think it is well worth the price. In terms of design,  all of the pipes seem to be the same  length which I seem to recall is an important consideration and this is not the case for the No. 1 pipe on the stock / che

[GSB]

ooooo, shiny!

Question: why do the pipes group in 1/4 and 2/3 pairs?

Its all about timing...

For an engine to get rid of its exhasut gasses, it has to pump them out of the cylinder. This of course uses valuable power. By tuning the lengths of the individial tubes, and pairing cylinders together such that they each exhaust into the manifold in turn, you can reduce these losses.  The way it works is at once ridiculously complex, and ludicrously simple all at the same time. So I'll try to explain it the simple way....

The first thing to realise as that the axhaust gases come out of the each cylinder in ashort pulse, occuring once every 2 revolutions of the crankshaft (think back to your basic four stroke cycle). These pulses consist of a high pressure wave leading a slug of gas into the manifold. Due to the wave nature of the pulse, its got high pressure at its leading edge, but at its trailing end its almost a perfect vaccum (trust me here, I know it sounds wierd, its all to do with velocities of moving gas and the fact that the exhaust valve has closed. It'll make sense in a moment...).

If you take 2 cylinders that fire and exhaust at equal intervals, (i.e. they have thier four stroke cycles 360 degrees out of phase, such that while  the first cylinder is exhausting while the second in compressing), and couple the exhasuts together as in the pic above, you can achieve timing whereby each cylinder is exhausting straight into the vaccum created by the exhaust pulse from the other cylinder... This reduced back pressure means that you are effectively 'sucking' the exhaust gas out of the cylinder, which greatly reduces the pumping losses, meaing more power is available at the crank... Clever eh?

Of course, all this is subject to very careful tuning, and when you understand how it works, you can begin to appreciate why big bore manifolds and exhausts can leave you with less power...

[Anonymous]

without wanting to go too OT...

That would seem to once and for all answer the question "are the precats failing a symptom or a cause of engine failure?"

Your description would seem to completely prohibit the sucking back of precat material into the engine? (stock manifold & exhaust)

[GSB]

without wanting to go too OT...

That would seem to once and for all answer the question "are the precats failing a symptom or a cause of engine failure?"

Your description would seem to completely prohibit the sucking back of precat material into the engine? (stock manifold & exhaust)

Not so I'm afraid James...

The above is just just a general overview on manifold design, and why, in certain applications, cylinders are paired together. Its not engine specific to the 1ZZ, and was never designed to be. Ididn't design the 1ZZ, so I cant say for sure what is happeing inside the manifold. But I do know that the above is just one of many industry standard practices. Other cars use a 4 into 1 system.... It depends entirely upon the engine.

There are further factors you havent considered. The above description asumes a straight flowpath to the collectors, as in themanifold detailed above. in our engine there are precats sitting infront of each of the cylinder exhaust ports, and their respective pulses. Place any obstruction in front of a pressure wave and you will get a reflection. This reflection wave could have the capacity to carry material back away from the cat towards to exhaust port. The 1ZZ also has vvti, which will radically alter the timing of the exhaust ports opening relative to the intake ports, and to the crankshaft postion. So, what works fine at one point in the vvti cycle is unlikekley to provide the same level of gas extraction at another point. It is entirely likely that overlap occurs between the exhaust and intake valves that  could allow some small portion of exhaust gas back into the combustion chamber, or that the exhaust valves are left open momentarily at the start of the intake stroke. Frankly, Im no expert on this and cant say its happening for sure, but it is another industry standard practice in engine design to allow this to happen. Its done in the name of lowering emmisions.

There is also one othe inescapable fact that we are yet to prove wrong....  

Without precats, these engines dont suffer from sudden precat death syndrome...

[northernalex]

how about this instead?

 m http://cgi.ebay.com/ebaymotors/TOYOTA-M ... dZViewItem m

(postage to europe 59 mecan dolla)

[Anonymous]

how about this instead?

 m http://cgi.ebay.com/ebaymotors/TOYOTA-M ... dZViewItem m

(postage to europe 59 mecan dolla)

It's the same as Che - they all come from China  s:wink: :wink: s:wink:

[roger]

Thats the guy I bought my <edit> short shift (pre TRD) </edit> from.

Excellent service and good shipping price. Would recommend him, definitely.