Auto RZ 272 Cams Emanage Ultimate TPS issue

[croboy]

Hi Everyone

 

I recently got my car back from the tuner, and I've been told that my car can only be driven after warming it up for 10-15mins, as the new cams I have put in are not pulling enough vacuum to run the car until the car is warm.

 

Here are my car specs:

 

1993 RZ

Stock Automatic (a340e)

Kelford 264/272 Camshafts (put in at TDC)

Stock ECU with E-manage Ultimate Piggyback

Munro Stage 4 Highflow Twin Turbos (Stock twins high flowed)

3" FMIC

Walbro 460 Fuel Pump

Sard 650cc injectors

 

It's Jap spec so it uses a MAP, not Maf sensor.

 

Can you guys tell me if that sounds right?

 

My car struggles to stay on sometimes even whilst warming up.

My tuner said its because it is Auto, and the cams I have put in with emanage do not work well together.

 

He said the new cams need to idle at 1k rpm, but the stock ecu is trying to idle the car at 650rpm.

 

He has tried to raise the revs with the emanage on startup, but the emanage and stock ecu are fighting against each other to keep the revs up. But when the car is warm its fine and won't shut off.

 

Is this a known problem with larger cams and piggyback ecu on auto ?

 

Does anyone know how to get the car working without having to wait 15 minutes to drive it every time, and it turning off when I put it in drive and try to accelerate?

 

Is there a setting in Emanage ultimate to raise the revs that maybe my tuner didn't know about? Someone mentioned TPS and voltage settings in emanage, but don't want to play around with anything unless I'm certain of what I'm doing.

 

The tuner said we can manually adjust the TPS screws, but then the car will always think I have my foot on the throttle, and will not gear properly. (it's auto)

 

If anyone knows of another way to get these cams working with emanage ultimate and auto tranny, I would really appreciate any help.

 

 

Thanks

[Chris Wilson]

I have wilder cams than that in my RB26 Skyline engine, and it starts on the key, in minus 12 degrees, no driver input needed, warms up smoothly and will drive away from stone cold should you not wish an idle type warm up period (i don't hold with warm up at idle myself) Whether it's a limitation of the ECU or the mapper i don't know. There's NO reason a decent map couldn't make such a cam / engine combination work properly assuming the ecu isn't somehow limited in what it can address.

[Frank Bullitt]

Any reason you went 264/272 on an auto? I thought a 256/264 was better suited to autos as it's staggered similar to the OEM set-up.

 

Bit of cam reading here - http://www.mkivsupra.net/vbb/showthread.php?85172-272in-264ex-vs-256in-264ex-cam-setup-test-results

 

Sorry I can't be of more help, hopefully CW will pop in...^ and there he is

Edited August 5, 2017 by Frank Bullitt
Too slow at typing. (see edit history)

[Chris Wilson]

Odd choice of duration for sure on an auto, but that aside it should cold start on the key, reaching in through the driver's window and warm up with zero extra input.

[Tricky-Ricky]

I would first try replacing the ECU coolant temp sensor, this will influence cold start considerably, i also cant see why the EMU should be a problem with lumpy cams either, although most piggybacks don't interface with the auto ECU well, but i would also expect the idle speed to be more on an auto.

[Krister]

I have wilder cams than that in my RB26 Skyline engine, and it starts on the key, in minus 12 degrees, no driver input needed, warms up smoothly and will drive away from stone cold should you not wish an idle type warm up period (i don't hold with warm up at idle myself) Whether it's a limitation of the ECU or the mapper i don't know. There's NO reason a decent map couldn't make such a cam / engine combination work properly assuming the ecu isn't somehow limited in what it can address.

 

RB26 uses airflow meters and do not react to cams as bad as a MAP car and Emanage is not a full standalone, its just and advanced piggybag.

Edited August 6, 2017 by Krister (see edit history)

[Krister]

To the OP. You could try to degree the cams so that there is not that much overlap. Emanage has its limitations as tuning idle and cold starts. Id consider going to less aggressive cams or another ECU.

[Chris Wilson]

RB26 uses airflow meters and do not react to cams as bad as a MAP car and Emanage is not a full standalone, its just and advanced piggybag.

 

 

My RB26 is on MAP sensor and M800 Motec, no AFM's. In actual fact it's the AFM metered engines that are very sensitive to cam overlap and duration with their associated air reversal, a MAP / throttle angle based system is FAR less sensitive and more appropriate for use with cams with levels of duration and overlap based on performance.

 

SBD did have a detailed resume of this pehenomenom but I can't find it with a quick Google, but they touch on it here. SBD build engines up to and including WRC and BTCC level, and have spent years on their engine dynos doing camshaft and management development:

 

"The only other common question we are asked, is people running road cars e.g. Astra 2.0L 16V or Cavalier SRI & GSI even the modern Ecotec engines as fitted to the latest range of Vauxhall cars. What kind of camshaft can I fit to my car? As well as all the problems already listed, you have one further problem to add and that is, that most production cars use what is known as air-flow metering.

 

They are either what is called ‘hot wired’ where the air being drawn across a heated wire changes the resistance according to temperature. So the faster the air, the cooler the wire becomes and from this the standard ECU is able to work out the amount of air being drawn across the air-flow meter.

The other type is what we call a ‘gate type’ and the faster the engine draws the air, the gate being sprung loaded, is sucked open further. Now for the problem – all camshafts generate a pulsing effect, this is where at a certain point in the engine cycle, the inlet charge becomes stationary (for simplicities sake). On a mildly tuned engine e.g. standard, this stationary pocket of air remains very close to the cylinder head. As you attempt to increase the cam duration on overlap to generate more power, this stationary pocket of air moves further and further up the inlet tract, eventually reaching the air-flow meter. Once this happens all air-flow metered systems become completely confused. So if you fit a camshaft which is a great enough improvement to give you an increase in performance, it will almost certainly produce the described effect and if you fit a camshaft mild enough not to cause the effect, your gains will be almost insignificant.

You might say, why not move the air-flow meter further away? Problem 1 is the reason most road cars are sluggish on throttle response is because the airflow meter is so far away from the head to begin with. The manufacturer has carefully worked out the position, which is as close as possible to the engine without causing the effect described. The further away you move the airflow meter the slower the throttle response becomes. So in effect, any gains you might have got from changing the cams is completely lost by the increasing delay of throttle response.

The only kind of system that can cope with this pulsing effect, is a throttle angle system such as the MBE systems we supply. They are pre-programmed with an amount of fuel for every at various speeds and throttle openings and as such are not effected by pulsing. There is also no delay because whatever speed you are at, and whatever throttle angle you achieve, the ECU knows immediately the pre-programmed amount of fuel to deliver.

So as you will see from our engine kits, if the replacement cams are used they are fitted in conjunction with either, deepening of the pockets of the standard pistons or replacement of the piston with up rated piston with deeper pocket & higher compression."

 

Oh and as an aside the commonest reason I see for the VVTi 2JZ engines to have poor performance and an unstable idle with the the DBW trying to compensate is when people rip off the "boring and restrictive" plastic trunking with the stock air box and stock MAF sensor holder, and fit shiny stuff. These kist often use bigger diameter pipes, or move the location of the MAF sensor nearer or further away from the valves. Bigger pipes make the sesnor read low as airr speed is greatly reduced. Moving nearer or further from the head changes the strength of the pulses. The engine has been METICULOUSLY mapped for where and how the MAF sensor is mounted, and its surrounding parts. Fiddling with ANY of this on a MAF sensor production engine will almost always give reduced performance and overall worse performance

 

 

Source: http://www.sbdev.co.uk/Do_Dont.htm

 

 

More info on reversal issues: http://support.moates.net/tuning-maf-systems-and-air-leaks/

 

 

Edited August 6, 2017 by Chris Wilson (see edit history)

[Krister]

It's not a fair comparison comparing a full standalone vs a stock ecu tricking piggybag. Of course my Supra with an AEM V2 starts right away with 2000cc injectors, E85 and 280 cams and idles nicely. Emanage is a whole different ball game and I've tuned a couple of them. Have you?

 

You can place the MAF further away from the engine to get rid if the air reversal.

 

But the best solution in this case would be less agressive cams or full standalone that retains the stock ecu to control the autobox.

Edited August 6, 2017 by Krister (see edit history)

[Chris Wilson]

It's not a fair comparison comparing a full standalone vs a stock ecu tricking piggybag. Of course my Supra with an AEM V2 starts right away with 2000cc injectors, E85 and 280 cams and idles nicely. Emanage is a whole different ball game and I've tuned a couple of them. Have you?

 

You can place the MAF further away from the engine to get rid if the air reversal.

 

But the best solution in this case would be less agressive cams or full standalone that retains the stock ecu to control the autobox.

 

That is why I said this in my first reply (post #2)

 

"There's NO reason a decent map couldn't make such a cam / engine combination work properly assuming the ecu isn't somehow limited in what it can address."

 

Moving the MAF sensor further away creates lag, it's just a crutch for when the engine should really be under MAP / throttle angle control.

 

I haven't mapped any, I am not a mapper, so I pay a pro mapper and only involve myself with "proper" management systems, I try to avoid difficult situations like the above Plus I don't believe the auto box has enough torque head room or enough suitable gear ratios to work well and reliably with the bigger single turbos, and more aggressive cam profiles.