VEMS + ABY + GT3071R 0.63 AR + 440ccm injectors

[Bram]

I am considering an upgrade to VEMS some day (need to do install a larger IC and Sachs race clutch first), since it seems the OEM MAF (420HP max?) is restricting the potential of my setup at this moment and in the future. But since I have no experience in electronic engine management systems I feel hesitant to buy VEMS.

How safe is it for an ECU-noob like me to start such a VEMS project? Can I easily blow up my engine, or are there a few parameters to be set with Megatune to avoid heavily detonation, etc.?

Another issue I have is how to setup the initial VEMS config for my Turbo and Injectors. Are there base-maps available, or can I start the engine with a map that is made for smaller/bigger injectors? I understand there are some maps available for the AAN, but I guess these are optimized for k24 and standard injectors?

Cheers

[Jamo]

Why do you think the MAF is restricting your setup out of interest?

Audiman, Mark Halligan & Doug_RS2 have all hit 550-600 bhp with standard motronics and MAF with a GT3582r

[terrybullwon]

Why do you think the MAF is restricting your setup out of interest?

Audiman, Mark Halligan & Doug_RS2 have all hit 550-600 bhp with standard motronics and MAF with a GT3582r

Spot on Jamo, Thats why i got rid of the SQ maf... No point over complicating things

[Bram]

Why do you think the MAF is restricting your setup out of interest?

Audiman, Mark Halligan & Doug_RS2 have all hit 550-600 bhp with standard motronics and MAF with a GT3582r

I read a few times that the max. voltage of the MAF was reached at around 420 HP (5V?) on this forum. I guess I need a experienced ECU mapper that can tune beyond this 5v signal then..... How is that done?

How did these guys tune their car if I may ask? Have they moved their MAF in between their turbo and IC?

What I do not understand is why most tuners are not able to tune the GT3071R like I have above 420 HP (at least I have not seen anybody proving that with this turbo), while some people with VEMS claim they run their GT2871R up to 460HP?

Or am I missing some important details here?

[Jamo]

I read a few times that the max. voltage of the MAF was reached at around 420 HP (5V?) on this forum. I guess I need a experienced ECU mapper that can tune beyond this 5v signal then..... How is that done?

How did these guys tune their car if I may ask? Have they moved their MAF in between their turbo and IC?

What I do not understand is why most tuners are not able to tune the GT3071R like I have above 420 HP (at least I have not seen anybody proving that with this turbo), while some people with VEMS claim they run their GT2871R up to 460HP?

Or am I missing some important details here?

The extra bhp above 420 is down to the little details which cost money, like full 3" exhaust, high lift cams, head porting ( most important ), large valves, lower piston CR so the boost can be pushed higher and ignition advance can be pushed.

Places like MRC and Automark in the UK can map above the 5v MAF limit by relying on experience and mapping the car on a real time simulator The MAF has been moved in these configurations to the pressure side.

There's a couple of threads one by Pekkas and Kalset and a few dyno plots I think in Ross's RS2 +1 turbo thread.

http://www.s2forum.com/forum/showpost.php?p=74175&postcount=73

http://www.s2forum.com/forum/showpost.php?p=74230&postcount=78

http://www.s2forum.com/forum/showpost.php?p=74591&postcount=87

[Nero]

Bram, hangjas. Zei ik toch al over die MAF. Hehehe. Maar je vriend geloven, nee hoor...

[aelred]

Can someone tell me or direct me to the VEM spec and supplier?

[S4 CRUISER]

Here you go Mr Smith

http://www.vems-group.org/

[GazzaG60]

the maf is a restriction and an overcomplication for a high power setup. why worry about moving it to the pressure side or will it hold out. its also a costly part to replace. removing the maf is also easy so why not if you can.

as a noob i wouldn't worry as long as you follow some basics.

get a wideband and EGT vems gauge. get a boost gauge, a good one too. personnally id get rid of N75 and use a proper boost controller too.

you need to be aiming for targer AF ratios of 14.5-15:1 for cruise and 11.5:1 ish for boost. you can get away with 12:1 and so but you are starting to creat heat.

you need to do a little research before hand. know oyur injector sizes and get some formula for the calus.

Read megamanual.com it applies to vems as its megatune.

with a decent base map you will have a good tune in around 2 hours. vems will target AFs for you so does some of the work.. i spent around 2 hours on the standard injector map for 321hp and 325lbsft at 5krpm with the injectors runnig static and AFs starting to drop towards the 13's so i aborted the run, wound down the boost until the bigger injectors arrived. fitted the 650cc and opened here up. needed to do about 30mins to convert to the 650cc's. car is in for an overhaul at present. was running 1.3bar beforehand.

hope this helps.

[pnanassy]

What do you need Sir?

pnanassy at gmail dot com

Peter

[Bram]

the maf is a restriction and an overcomplication for a high power setup. why worry about moving it to the pressure side or will it hold out. its also a costly part to replace. removing the maf is also easy so why not if you can.

as a noob i wouldn't worry as long as you follow some basics.

get a wideband and EGT vems gauge. get a boost gauge, a good one too. personnally id get rid of N75 and use a proper boost controller too.

you need to be aiming for targer AF ratios of 14.5-15:1 for cruise and 11.5:1 ish for boost. you can get away with 12:1 and so but you are starting to creat heat.

you need to do a little research before hand. know oyur injector sizes and get some formula for the calus.

Read megamanual.com it applies to vems as its megatune.

with a decent base map you will have a good tune in around 2 hours. vems will target AFs for you so does some of the work.. i spent around 2 hours on the standard injector map for 321hp and 325lbsft at 5krpm with the injectors runnig static and AFs starting to drop towards the 13's so i aborted the run, wound down the boost until the bigger injectors arrived. fitted the 650cc and opened here up. needed to do about 30mins to convert to the 650cc's. car is in for an overhaul at present. was running 1.3bar beforehand.

hope this helps.

THat sounds all good! Thanks. I was already wondering if it would take me weeks to get a base-map working, but that seems to be doable

I will take a read at megamanual.com

[K7ERG]

pnanassy knows his stuff and a trusted seller.

I bought my Vems from him and have had good support throughout.

Craig

[A80Avant]

my issues with vems although a brilliant solution for anyone willing to fiddle around the management,are these:

1) rough idle,not close to motronic even with the latest versions.You need loooooong hours to manage to get it close to right and even then it is not as good.

2)consumption figures not working,and probably never will.Some argue that if you fit larger injectors they dont tell the truth anyway,however i use the 440 injectors which may take me to 500hp figure and with the dash setted correctly i can get a close figure to what im actually consuming which is not bad

3)The fine tuning a specialist will do to your car,will be very hard to achieve with vems if you decide to do things totally on your own.For me i dont want to spend months to tune the car because by then i will most likely have something either needing replacing,either a boost leak,or i will want even more power...etc....So lets say you take VEMS to a tuner to make it happen.Sure megatune is a well known software for tuners,but then again,everytuner has it's own backup of aftermarket ECU supply to give you and probably will not bother making the fine tune you need(let alone some tuners will turn you down to begin with !!
4)You can forget about reading the fault codes of the car...Unless you carry the motronic in the trunk and switch back and forth.Then of course you will need the to also carry the MAF,switch the cranckshaft position sensor(not sure,i think you dont have to anymore according to vems) etc.

On the other hand,you loose the MAF!!!

Questions in my mind are...

1)are you going to make a drag car or an everyday fast car?

If you are making a drag car,then you dont care about rough idle,or anything and you are going for high hp range,more than 550-600 side.
If you are making a fast everyday drivable car,(faster than our setup Bram,the 400ish figure) then i believe that the car should feel nice and have all motronic features there.So why not just go to someone who can incorporate a larger MAF to the setup,one that is not that costly and you can just change the sensor only,rather than the complete thing!I have seen a couple of RS2 with that scania 90mm MAF with interchangable sensor and not a the thread ones we have.So it can be done,and also without using the obsolete and agreed very expensive SQ maf either!
Also,if you get a large maf,i dont thing you will have many failures with it and that is because it will be able to handle the power and the air.My MAF hasnt had any problems so far and i have had it about a year now.AND it is working at it's limit too!I could get a larger one and get away with it for a looong time.

[Jamo]

my issues with vems although a brilliant solution for anyone willing to fiddle around the management,are these:

1) rough idle,not close to motronic even with the latest versions.You need loooooong hours to manage to get it close to right and even then it is not as good.

2)consumption figures not working,and probably never will.Some argue that if you fit larger injectors they dont tell the truth anyway,however i use the 440 injectors which may take me to 500hp figure and with the dash setted correctly i can get a close figure to what im actually consuming which is not bad

3)The fine tuning a specialist will do to your car,will be very hard to achieve with vems if you decide to do things totally on your own.For me i dont want to spend months to tune the car because by then i will most likely have something either needing replacing,either a boost leak,or i will want even more power...etc....So lets say you take VEMS to a tuner to make it happen.Sure megatune is a well known software for tuners,but then again,everytuner has it's own backup of aftermarket ECU supply to give you and probably will not bother making the fine tune you need(let alone some tuners will turn you down to begin with !!
4)You can forget about reading the fault codes of the car...Unless you carry the motronic in the trunk and switch back and forth.Then of course you will need the to also carry the MAF,switch the cranckshaft position sensor(not sure,i think you dont have to anymore according to vems) etc.

On the other hand,you loose the MAF!!!

Questions in my mind are...

1)are you going to make a drag car or an everyday fast car?

If you are making a drag car,then you dont care about rough idle,or anything and you are going for high hp range,more than 550-600 side.
If you are making a fast everyday drivable car,(faster than our setup Bram,the 400ish figure) then i believe that the car should feel nice and have all motronic features there.So why not just go to someone who can incorporate a larger MAF to the setup,one that is not that costly and you can just change the sensor only,rather than the complete thing!I have seen a couple of RS2 with that scania 90mm MAF with interchangable sensor and not a the thread ones we have.So it can be done,and also without using the obsolete and agreed very expensive SQ maf either!
Also,if you get a large maf,i dont thing you will have many failures with it and that is because it will be able to handle the power and the air.My MAF hasnt had any problems so far and i have had it about a year now.AND it is working at it's limit too!I could get a larger one and get away with it for a looong time.

excellent summary

[pnanassy]

well,on the fault code reading:
with a proper standalone you will find the problem even faster with motronic.You can clearly see "all" sensors on one screen with vems.

Peter