278 replies to this topic

[ShinyAndy]

It may well be quicker to stretch the lower gear, rather than have to change up and get the power on again.

Not if you're sat with no power for 1000rpm it won't be, far better off changing gear and being in the power band, maybe the turbot is different but if I change gear at peak power I'm straight back into the powerband in the next gear too

[UKspeedster]

It may well be quicker to stretch the lower gear, rather than have to change up and get the power on again.

Not if you're sat with no power for 1000rpm it won't be, far better off changing gear and being in the power band, maybe the turbot is different but if I change gear at peak power I'm straight back into the powerband in the next gear too

No definitive proof either way, but I would argue that there could potentially be situations where having the additional flexibility is beneficial.

It would be churlish of me to suggest it is always better changing up at the higher rev limiter, but you have to admit it's not unusual to occasionally bounce off a rev limiter set only a little beyond 6000rpm (even without the high lift cams), as power drop off is only slight at that stage?

[clipping_point]

I think you can see in the power graphs that the power dies at 6500 rpm, so I would go for the cams AND an improved intake. It is clear from observing the dyno results of Dudes engine that to shift the power curve towards higher revs, you need to improve the flow. And the same applies for racier cams. To benefit from them you need to eliminate the restrictions. Once that is done increasing the revs will make enormous difference!!!!!!!!!!

[VIX]

Here's my results from 14 September at about 9000 miles. Initial bhp of 141.7 is disappointing but 11.4 bhp hike as a result of Stage 2 seems to be the norm. It'd be interesting to know why the power is down though.

[damontite]

I assume you had a re-map, removed the pre-cat and had a cam kit, and a full exhaust? I had stage 2 and my vx went to 167bhp. Cheers Damon Tite

[Jim_Cross]

Stage 2 doesn't include cams - that sounds more like stage 2.5 (I think stage 3 includes headwork as well) 11bhp doesn't sound right for a stage 2 though - I thought the Milltek alone should give 9-11bhp, so I would expect more like 20bhp including the remap

[VIX]

Thanks for the responses. I had the standard AmD stage 2 - full exhaust, Viper and remap. Graphs show: Before 141.7 bhp @ 5876 and 148.3 lb/ft @ 4174 After 153.1 bhp@ 5752 and 155.1 lb/ft @ 3998 Any ideas why this could be below the average?

Edited by VIX, 20 September 2004 - 06:03 PM.

[Jim_Cross]

That sounds well below average - looking at the table, all the other stage 2s are between 167bhp and 175bhp, although some of these were done when AmD's rolling road was overreading. Could be bad petrol, or an ECU problem? Also, the engine is still pretty tight at 9000 miles

[VIX]

Jim, I had just refilled with Optimax the night before AmD so hopefully it's not fuel although I reckon it's pinking a bit eg pulling away from roundabouts. AmD say this shouldn't be a problem with all the sensors and anti-knock devices. I've done about 300 miles since getting the car back and plan to do Wales/Anglesey and will probably then pop back to AmD and see what they say. (You're not going to Wales or Anglesey are you?) Steve

[Jim_Cross]

I'm not going to Wales no, bit too far for me Good luck getting it sorted. Might be worth a trip to Crownhill to get it plugged in to the Tech 2 to see whether there is an ECU problem. However, there is a charge for using the Tech 2

[BogBrush]

Those figures do look a little weird. Last time I had my vx on a rolling road, it was pushing 155bhp and 160lb Torque. That was only with a K&N filter,Vauxhall Sports exhaust and the pre cat removed.

[VIX]

Might be worth a trip to Crownhill to get it plugged in to the Tech 2 to see whether there is an ECU problem. However, there is a charge for using the Tech 2

Presumably AmD don't have a Tech 2? Will Crownhill be bothered that I've had a remap?

[VIX]

Those figures do look a little weird.
Last time I had my vx on a rolling road, it was pushing 155bhp and 160lb Torque.
That was only with a K&N filter,Vauxhall Sports exhaust and the pre cat removed.

[clipping_point]

Where did you do this test? If the car feels good then there should be no problem. Also it was a very warm day 27 °C. And how are the tyres?

[VIX]

Where did you do this test? If the car feels good then there should be no problem. Also it was a very warm day 27 °C. And how are the tyres?

The test was done at AmD before and after the Stage 2. Tyres have a couple of thousand miles left on them - or a couple of track days!

I am not sure if the car feels good - sounds daft but it is now so different not least of which is the noise and reverberation and the effect this has on the perception of speed and when to change gear. I I feel as though it is revving less freely but this is just a feeling and I think the proof will be at Anglesey on Monday. Ideally I can get someone with a similar car to drive mine.


PS. This is not meant to be any criticism of AmD who are happy to investigate any issues I have and I plan to pop back to them Saturday week. There is also the question of whether the car was down on power to start with.

[Jase_MK]

Vix, I'm quite happy for you to drive mine if you want. Similar spec to yours but no remap, so yours should feel noticeably quicker. Give us a shout if you want to find a quiet road in MK one evening.

[Foxy]

What does the graph look like VIX? Is it smooth all the way up? Which technician did the work?

[VIX]

Foxy, Here's the bhp graph. According to the print out Gary did the work. Jase, I'm pm'ing!

[Foxy]

ooh...that's not great below 4k is it?

[jules_s]

Its gotta be cos the thing is hardly run in surely? I mean theres an absolute mile of difference between a 9k VX and a 20k VX