Manifolds Orignals and Act

[hiltonig]

Does anyone know if the manifolds are stainless or mild steel as standard ??, I am in a bit of a dilemma as I want to go for the SC500 conversion but it wont fit with the ACT manifolds which I have already got ( not fited yet )So the alternative is to keep the originals and get them camcoated and drilled ready to fit a wideband lambda. Any one had their orginals camcoated and did you have any problems ?

[clive f]

the originals are mild steel, have had mine camcoated now for 2 years and no problems.

[hiltonig]

did you get the cat Y piece done as well ???

[spend]

If you remove the precats you can get the manifolds coated internally as well, this is advised so that heat isn't retained in the metal (conducts back to heads..)

If you have a decat Y-piece you can have it done internally also, I had one of each coated, 4ish? years ago & still fine.

Dave

[GreenV8S]

I thought the originals were a rather feeble grade of stainless, not mild steel. They certainly don't seem to suffer from as much corrosion as you'd expect from mild steel.

[hiltonig]

ok for my benefit, the precats are in that lump before the bend ??, any downside to precat removal ??, dont want to make the car too loud as its going to have the act exhaust and that will be enough, how do get the precats out then ??

many thanks

[macdeb]

I have the original [stainless] exhaust. I sent it to ACT to have the precats removed and non-reversal cones [think that's what they called them] which from what I remember help with the draw of gases. Also inside [aswell as outside] of manifolds coated which also apparently helps with gas speed because of retained temp'. Main cat kept and ceramic coated outside only.
The coating helps keep under bonnet temp' down so seems logical upgrade if your going supercharger route because of temps' and keeping exhaust gases flowing efficiently. [Of which I'm also considering at the moment]
I don't know enough technically to quantify the above or to prove improvement, but went for it any way. Looks loads better under bonnet and don't seem to get such a sun-burning blast of heat when bonnet is opened. Also, know of chap with Cerbera and he says there is definatly an improvement in the cabin temp'.

PS they are in the lump before the bend.

Edited by macdeb on Sunday 10th February 10:20

[That Daddy]

GreenV8S said:

I thought the originals were a rather feeble grade of stainless, not mild steel. They certainly don't seem to suffer from as much corrosion as you'd expect from mild steel.

they def aint mild steel

[Uncle Fester]

hiltonig said:

Does anyone know if the manifolds are stainless or mild steel as standard ??, I am in a bit of a dilemma as I want to go for the SC500 conversion but it wont fit with the ACT manifolds which I have already got ( not fited yet )So the alternative is to keep the originals and get them camcoated and drilled ready to fit a wideband lambda. Any one had their orginals camcoated and did you have any problems ?

Which ACT manifolds won't fit with the SC kit?

I intend to go SC too. I decided to fit an Emerald ECU first to provide better control for this. If you take this route then you have one wideband sensor in the main cat. I chose a V8 Enhancements and Clive can fit you a new wideband boss in it. Then you just fit bungs in the original lambda holes.

I also went for an exhaust gas temperature sensor in anticipation of forced induction. This fits in the manifold as near the exhaust valve as possible on the hottest cylinder. While you have the manifolds out then you may as well put the boss in and get the pre-cats removed if you haven't already.

[clive f]

That Daddy said:

GreenV8S said:

I thought the originals were a rather feeble grade of stainless, not mild steel. They certainly don't seem to suffer from as much corrosion as you'd expect from mild steel.

they def aint mild steel

well if tvr used stainless then the grade must have been extremely cheap crap, mine were quite rusty and had to be shot blasted before they were sent to be camcoated

[That Daddy]

clive f said:

That Daddy said:

GreenV8S said:

I thought the originals were a rather feeble grade of stainless, not mild steel. They certainly don't seem to suffer from as much corrosion as you'd expect from mild steel.

they def aint mild steel

well if tvr used stainless then the grade must have been extremely cheap crap, mine were quite rusty and had to be shot blasted before they were sent to be camcoated

Yes it is crap,but better than mild steel that would disapear overnight with the lack of use that most of these cars see

[hiltonig]

Talking to SC its the ACT Sports setup that dont fit with the SC500 not the refirb orignals that they offer. So I am going to fit them Emerald too, Mr Fester you mention the EGT probe where did you put it exactly as I dont which s the hotest cylinder ??, I am making provision for it if I do the SC conversion.

Edited by hiltonig on Monday 11th February 06:36

[Uncle Fester]

hiltonig said:

Talking to SC its the ACT Sports setup that dont fit with the SC500 not the refirb orignals that they offer. So I am going to fit them Emerald too, Mr Fester you mention the EGT probe where did you put it exactly as I dont which s the hotest cylinder ??, I am making provision for it if I do the SC conversion.

Edited by hiltonig on Monday 11th February 06:36

The principle is that the EGT sensor goes as in the manifold, as near to the valves as possible, on the cylinder that receives engine coolant last.

Going off topic slightly, V8D told me that the EGT would drop slightly just prior to and during pinking or detonation.

I had hoped to use EGT as a type of knock sensor, since Emerald doesn’t offer a knock sensor option. I assumed that since I had believed knocking caused increased cylinder temperatures this would show on the EGT sensor.
Does knocking in fact cause a temperature rise?

Or

Why does the EGT fall when the engine knocks?

Edited by Uncle Fester on Monday 11th February 08:08

[hiltonig]

Any idea of the thread size on the EGT sensor, was going to put a bung somewhere before I send them off to camcoat

[GreenV8S]

I don't know about the EGT dropping during knock, but I sure as hell wouldn't want to rely on that as my knock detector. How about getting an external knock detector and alarm? You may even find that your ECU can cope with the alarm input and drop into a 'safe' mode even if it doesn't have active knock avoidance.

[Johno]

Hiltonig

Which of the ACT manifolds do you have ? The new sports one or the original ones just in stainless steel ?

Edited by Johno on Monday 11th February 21:28

[hiltonig]

I have the new sports type with racing cats

[Uncle Fester]

GreenV8S said:

I don't know about the EGT dropping during knock, but I sure as hell wouldn't want to rely on that as my knock detector. How about getting an external knock detector and alarm? You may even find that your ECU can cope with the alarm input and drop into a 'safe' mode even if it doesn't have active knock avoidance.

The EGT drop surprised me; I would have expected the opposite.

When I found out Emerald didn't have a knock sensor facility, I spoke to Dave Walker. He said that they were very difficult to dependably implement on an aftermarket system. Better not to have something unreliable. However, if enough people demanded it or a reliable way to do it then it would be added.

I wondered if the EGT could be used as a trigger for knock sensing. I suspected that EGT would spike with knock. I reasoned that if the temperature caused by knock was higher than anything else then we could induce knock, record the EGT associated with knock onset. Once we knew that temperature, then we could set the ECU to take action to prevent knock at an EGT just below knock onset. This seemed a better idea than waiting for knock to happen and then deal with it.

I ran the idea past the guys at V8D who were doing my Emerald install at the time. They said that EGT actually falls with knock onset. I don’t recall why that should be (can anyone explain?) so the idea was dead.

Can anyone think of something else that happens just prior to knock onset that could be used as a preventative trigger?

I did wonder if we could get the pattern of the EGT drop to trigger, but this would demand substantial ECU changes to recognise a characteristic pattern.

[GreenV8S]

I can't imagine why the EGT would drop, but even if you had some way to detect that against all the other factors affecting EGT the thermal response time would surely render this useless as a way of detecting knock. Acoustic knock sensors are the obvious answer. Ideally you'd have a mapped driver built into the ECU but standalone (unmapped) systems seem to work OK in practice. Given a binary knock signal into the ECU I wouldn't have thought it was too challenging to implement an ignition retard/readvance algorithm.

[spend]

Haven't there been a few articles by Dave Walker 'attacking' knock sensing?

Wont you get decreased burn when reaching knock which will reduce gas temp? I'm not sure the EGT is exactly related to spot cylinder temperatures anyway, it can be used as an indicator but not as an absolute measure IYSWIM.

Dave