Lack of low down power - plots added

[pablo_vr6 0]

had my car on the rollers last week with Mikes from the forum.

 

my mods:

 

carbonio intake

decat

 

his mods:

 

ss exhaust

turn2 intake

fse

 

now we both peaked at near exactly the same figure (186bhp @ fly / 164 or so @ wheels) but his power came on earlier than mine meaning his car was more eager at lower revs. this is backed up by a 3rd gear roling start side by side where he gets away from me then it evens off.

 

The RR guy was sure its the MAF being a bit suspect but we swapped MAFs last night and there was no difference in feel at all.

 

Im gonna go get the overlaid plots tonight and will post them but looking for any suggestioons at this point :)

 

cheers

-pablo

[pablo_vr6 0]

forgot to say vagcom is clean.

 

and the co2 readings fine.

[Kevin Bacon 5]

Did you reset the ECU after you swapped MAFs? Might make a difference as the ECU will then be forced to use it if it was bypassed and using the Throttle position sensor.

 

As for the power coming in earlier, could be a few things, wheel size (accelerates better on 15s, no question), intake method, general health of the engine etc etc....

[pablo_vr6 0]

damn didnt think to reset the ecu

[dr_mat 0]

164 at the wheels is pretty healthy.

[pablo_vr6 0]

yeah the peak isnt the problem it seems lazy to get there.

 

now one option is that mikes mods are really working and thats the difference but Id imagine they should be fairly similar.

[gibber 0]

How do you reset the ECU?

sorry to hijack your tread a little but Im cursous as to how, why and when you would do this?

[Henny 0]

gibber_2k, the VR6 ECU will go into fail safe mode if it detects an out of limits reading from some of its sensors... To reset it, disconnect the power to it (normally easier to dis-connect the battery!) for about 30 seconds... If you use the search, then you'll find the complete procedure... 8)

 

pablo_vr6, it could be as simple as how the car is normally driven and how it's been treated since new... I've driven quite a few cars in my time (understatement there! ;) ) and I've yet to drive 2 cars which are identical in the way they perform even ones I've built the engines for myself!

 

Power and torque seem good for both cars, so I doubt there's a real problem... but I know what you mean about wondering why one is "lazy" and the other isn't... :|

[dr_mat 0]

Tappets or timing chains.

A lack of smoothness can make the difference between an engine that's perceptively torquey-er than others.

Mine seems to really benefit from a long run, clearing out the coke and quietening down the tappets. For the following week or so it's a flying machine from almost no revs. But two or three weeks of commuting later and it's back to running a bit rough and sounding like a bag of spanners.

[pablo_vr6 0]

cant say I notice anything like that dr_mat,

[dr_mat 0]

perhaps you don't have sticky tappets then!

[pablo_vr6 0]

lol thats all id need :)

 

Im gonna go get the plots printed tonight so more info to follow !!

[gibber 0]

Thanks Henny I found this http://the-corrado.net/.archive/forum/download.php?id=1995 very helpfull could do with being in the how-to guides I think.

[Kevin Bacon 5]

Try putting the standard induction system back on and see if Mike pulls away in 3rd again, oh and put the 15s back on aswell because those 17s won't help the acceleration!

[pablo_vr6 0]

both cars have similar induction and rims

[Kevin Bacon 5]

Well you'll just have to get the MAF issue looked at then, or just accept his is better :)

[pablo_vr6 0]

back to the rollers :)

[MikeVR6 0]

Don't forget, I've a de-cat and ported throttle body too Pablo :)

 

After you left I ran my other VR6 with the MAF disconnected just to see what happened.

 

As expected, it wouldn't idle at all. I had to hold it at about 1000RPM to keep the engine running.

There was quite a strong whiff of petrol too.

 

Presumably these are the same symptoms a dead MAF exhibits?

[pablo_vr6 0]

oh yeah :oops:

 

was up at Davys and got the plots printed off. if its not something wrong with my car then Im getting a ported TB too ;)

 

at 3k revs the diff is 20bhp :shock:

 

seems the MAF can go a little bit showing bad mpg and lastlustre performance then the next level is total fecked. that one i showed you is the latter :)

[Kevin Bacon 5]

So the ported body makes a difference then :wink:

 

Certainly does when you add a Schrick VGI and 268 cams into the equation too :mrgreen:

 

With those you actually get less torque at 1500 rpm than you do with a standard VR6, but you don't actually feel it on the road, very bizarre.

[pablo_vr6 0]

ok here are the plots:

 

the heavy line is my car. the two wick ones are my car before the carbonio and decat and the best one is mikes.

 

the torque plot really shows the difference.

[Kevin Bacon 5]

The torque plots don't make sense at all.

 

Your power plot looks good.... you're worrying about nothing, especially as the difference on paper equates to a car length's distance when pulling away in 3rd in real life......and then you catch up again!

[pablo_vr6 0]

yeah Im not *that* worried about the power but i think my torque plot show a severe lack of grunt at low revs.

 

and I wanna know why :(

[crazymarcel 0]

Cant quite understand your torque graph pablo, whys it look like that or am i bein stupid

 

Here's mine if you want a bit of comparsion

[pablo_vr6 0]

your torque plot starts earlier than mine - mine only kicks off at 3k.

 

they are 4 plots overlaid btw