VT Performance Problems - Not always?

[Jamie_87]

i think it might be the trans getting a bit hot making u lose performance also, cos my car gets a lil sluggish when it gets hotter engine revs fine, although its alot better since i put the 2.5in cat back exhaust,im getting a full trans service done soon, so hopefully should make it abit better.

 

[Lord-Data]

Well, soon enough (10-12 weeks) i'll be getting injected LPG on this baby, followed by extractors and 2.5" system, and then eventually probably a higher PSI pulley for the charger, so if theres a fundamental problem in the system somwhere, i wanna pin it down now

 

[danja]

car will always go harder at when its cold cos there are more oxygen particles in the air, more oxygen in air equals greater igintion.
dont spend money on o2 sensors its waste of money and pointless coz it's just basic chemistry at work...

Clearly you've done your research here... the beauty of public forums epitomised :bang:

Anyway, on the cold-air front you were stumbling in the right direction; colder air is denser air, so you're getting more air into the engine (a bit like a really REALLY weak turbo/supercharger)

As for the O2 sensors, I suggest you try pulling out your sensors and letting them dangle in the engine bay for a week and see how you go with performance and ecomony. You'll change your mind pretty fast.

 

[glowworm]

no power

Hey this is glowworm i had the same problem with my vt v6 i had everything replaced all sensors and still nothing was working . the auto elec checked the computer it was fine no codes were coming up .I got the auto elec to put in a second hand computer that i got from a wreckers and guess what the power problem is gone i have full power again.Try putting in a nother computer it will be the problem..Glow....:yeah:

This is an odd one thats bugging me ..

Sometimes, the car goes perfect .. hammers like a S/C V6 Should ..

But other times, and often when its warmer, not 100% is its related, but it seems to be on hotter days (no, nothing to do with A/C), somtimes, it just "wont go".. struggles to get going, basically ..

It drives, just really lacking in power .. can happen in both take offs from standing, you floor it, and it revs to about 2000-2500, and kinda sits there, slowly accellerating, but drinking fuel (according to trip computer) as if it was going fast!

other times is when you'd change down to take over, for example.. you plant your foot, feel it change down gear, revs go to about 2500, and it just kinda maintains speed, barely slowing up, but your foot can be almost on the floor!

It actually feels like it sometimes doesnt know you've put your foot down that far, it just doesnt seem to react to it. I've already had the TPS replaced, mechanic suggested maybe replace exhaust system, but can't explain why sometimes it works fine .. hes kinda just said "live with it"

Any suggestions on what to look for/replace?

O2 sensors have also been replaced, and comp is chucking no codes..

Thanks in advance

 

[Lord-Data]

Actually thats an interesting point .. i had noticed, some time back, that after the battery had been disconected for a little while for whatever reason, for a short while, performance is right back up there as it should be .. perhaps it is the computer, and resetting it temp helps.. interesting ..

is the ECU on the VT user changeable/accessible? I know it was on the VL, is it similar on the VT?

 

[accentstencil]

..

is the ECU on the VT user changeable/accessible? I know it was on the VL, is it similar on the VT?

I think its easy enough to do. But think you will need to get your new ECU linked to the BCM.
How has it been going in the heat? Mine is really bad at times. Let us know if resetting helps.

 

[hammono]

Hey I have the same problem in my VX and have had alot of mates tell me the same thing with ther VT's. All these things i should try but with my car the weather is not the reason for it as it will happen even on a really cold day, and it performs better at round lunch time then early in the morning. i have also recently fitted a 2 1/2 inch catback and it does help a little bit yet it will still has a tendency to feel underpowered at times..

 

[Tonsta V6 S/C]

Welcome to the World of "Knock Retard"

If using inferior quality fuel, running stock or higher boost or hot weather the ECU Engine Knock Sensors will pick up a bit of incidental detontation and start removing Timing from your Spark Timing Advance Map.

The ECU Knock Interaction can remove as much as 14* Timing moving it into negative timing a some points to try and curb would-be spiralling detontation.

It is very normal for a Super6 to feel good sometimes and crap other times. It will be most noticeable on hot days or times which the engine is very hot from being driven a long time.

Ways to cure:
1) Run ONLY BP Ultimate 98+RON Fuel ALWAYS
2) Nulon Pro-Strength Octane Booster
3) HeatShield for LHS Exhaust Manifold
4) Improve CAI (No PODS !!)
5) Cooler Thermostat (81*C)
6) In-Cabin Fans Switch
7) Intercooling

You can reduce the "Good Day" vs. "Bad Day" power-up and down moods of the Super6 by following the simple above guides.

Hope this helps.

Regards

Tonsta

 

[accentstencil]

Welcome to the World of "Knock Retard"

If using inferior quality fuel, running stock or higher boost or hot weather the ECU Engine Knock Sensors will pick up a bit of incidental detontation and start removing Timing from your Spark Timing Advance Map.

The ECU Knock Interaction can remove as much as 14* Timing moving it into negative timing a some points to try and curb would-be spiralling detontation.

It is very normal for a Super6 to feel good sometimes and crap other times. It will be most noticeable on hot days or times which the engine is very hot from being driven a long time.

Ways to cure:
1) Run ONLY BP Ultimate 98+RON Fuel ALWAYS
2) Nulon Pro-Strength Octane Booster
3) HeatShield for LHS Exhaust Manifold
4) Improve CAI (No PODS !!)
5) Cooler Thermostat (81*C)
6) In-Cabin Fans Switch
7) Intercooling

You can reduce the "Good Day" vs. "Bad Day" power-up and down moods of the Super6 by following the simple above guides.

Hope this helps.

Regards

Tonsta

Thanks for the advice, very interesting. I'm just not sure if you mean that you have to do all 7 of these things, or several, or just one.

 

[WAGON MAN]

Tony is that applicable for a n/a V6 as well?