Opinions please MAP or throttle angle

[Meatball]

Im in the process of installing one of Phil`s Plug and play Megasquirt systems brought through V8Developments, excellent bit of kit by the way and as Mac mentioned in an earlier thread excellent customer support from Phil (Extraefi) and Shaun (V8D)i couldn’t agree more with his comments.

As i know almost nothing about tuning im interested to know your opinions on mapping via MAP or throttle angle there seems to be quite a difference in opinions on this.

Cheers

[Pupp]

Probably dependant on the cam you are running, v8s with long overlap cams don't make much of a depression to measure low down... there's a facility on my ecu to trim from MAP while using TP as the primary reference but not tried it so far.. think TP is likely to be easier to map DIY

[daxtojeiro]

As a general rule of thumb if you have ITBs then you will have no map as soon as you touch the throttle so that usually goes TPS based. If you have a plenum with a single throttle (RV8 intake) then usually you can go MAP. If you go MAP and find you have a high value at idle (65KPa or greater) then Id go TPS. If you have anything lower then MAP is the better route.

Its my opinion that MAP is a better, smoother, more accurate method as long as your engine is suitable. I have 2 throttles on my RV8 intake and I run MAP without any issues.

To run TPS then you need a good range off the TPS sensor, so 0-5V. I seem to recall you said you had 2-4V or something similar, if you want to go TPS then youll need to resolve that.

TPS based runs on all setups and a lot of tuners prefer it, but I personally dont, no real reason, just my preference.

I think you said you had 45KPa at idle, if thats the case then you have a great setup for MAP,
Phil

[K4000JB]

Anymore Ideas on this I would like to hear other views on this
TIA

[350Matt]

I've tired both and the MAP set-up was a lot harder to, well map as you can't just set a throttle stop and hold a load site and then drive up that line of the map.

now the finished article with MAP was slightly (and I mean slightly) smoother than the TPS driven version and of course it naturally compensates for atmospheric pressure changes.

However I'd stick with TPS mainly because its a damn site easier to work with and diagnose issues with when you have problems , plus it tended to give better throttle response

[dnb]

My car with MAP based load has good throttle response. It uses TPS for acceleration enrichment, so it's really the best of both worlds.

Yes, it's more effort to tune, but most of this can be automated.

[Meatball]

Out of interest What ECUs are you guys using?
And what makes mapping via MAP more difficult?

[daxtojeiro]

Meatball said:

Out of interest What ECUs are you guys using?
And what makes mapping via MAP more difficult?

Map is harder to tune on the fly as you tend to drive through the points where you need to tune, where as in TPS you can simply put your foot on the throttle to the point you want to tune on the load scale.

This isnt a real issue if you datalog the runs and then run the datalog through the tuning software as it will work it all out for you and tune the map. But this isnt fool proof, so it does make it a little harder.

I get around this by applying some brake whilst driving and then you can use the brake / accelerator to get the MAP to the point on the scale you want to tune, its actually quite easy to do, but obviously this will heat the brakes up so you cant do it too much.

As for responce, you MUST tune the fuel map without any enrichments on, so Accel enrichment, EGO correction, etc, turn it all off if tuning on the fly, and get the map correct. Then add in Accel Enrichment and you will get a good responce, whilst all the MS ECUs can use TPS or MA{ for Accel, with MS2-3 you can blend TPS and MAP responce together to get a really accurate enrichment.
Phil

[fatjon]

Maybe rather too late but the megasquirt hybrid alphaN/MAP works quite well. AlphaN up to 2500 rpm then phases in speed density. Nicely overcomes the lack of a clean vacuum signal at low RPM and idle. Used it to good effect on a few engines with hot cams and ITBs.

[daxtojeiro]

fatjon said:

Maybe rather too late but the megasquirt hybrid alphaN/MAP works quite well. AlphaN up to 2500 rpm then phases in speed density. Nicely overcomes the lack of a clean vacuum signal at low RPM and idle. Used it to good effect on a few engines with hot cams and ITBs.

Thats a good point, I always forget about that function
Phil