Discussion
Finally got my car back from Gary's on friday after the underboosting issue had been sorted out. Replaced the ECU plus a few other bits including wiring/fuel pump.
Now produces 419bhp and boosts properly. Apart from the fuel pump, the car is standard.
Friday was a bit wet so couldn't really test the car. Went out in it yesterday and MY GOD this thing absolutely flies!! It is so much better than when I bought it. The acceleration is savage and relentless no matter what gear I'm in. This makes me think the boost issue was there from the start and I just didn't notice.
A huge thanks to Gary and Mike for their help in sorting this...I'm a lot happier knowing the car is capable of producing close to its factory quoted figures!
Now produces 419bhp and boosts properly. Apart from the fuel pump, the car is standard.
Friday was a bit wet so couldn't really test the car. Went out in it yesterday and MY GOD this thing absolutely flies!! It is so much better than when I bought it. The acceleration is savage and relentless no matter what gear I'm in. This makes me think the boost issue was there from the start and I just didn't notice.
A huge thanks to Gary and Mike for their help in sorting this...I'm a lot happier knowing the car is capable of producing close to its factory quoted figures!
gadgeroonie said:
Alex - there are a few more horses under the bonnet (sorry clam) waiting to come out if you want them. I will chat it over with you next time we meet
most m400's make about 380 - so its fair to say she is running rather well
is it worth posting up the before and after power graphs ?
most m400's make about 380 - so its fair to say she is running rather well
is it worth posting up the before and after power graphs ?
Not the best idea youve ever had, 420 bhp from a standard M400 is about it unless you change the valve springs, Noble skimped here and if you run higher boost you'll knacker the valve seats. I know i did it.
the rpm signal was taken directly from the igniton system of the vehicle - it is accurate to 1rpm
I would think that the car was not revved to the rev limiter - ie the run was aborted as power dropped off
"Yes, why does it "give up" at around 6200 rpm?"
could be several reasons - but from what i've seen Nobles do not make big power at high rpm. It could be down to a restictive exhaust, cylinder head, exhaust housing, loss of boost, or just less ign timing at the top
to be fair most engines lose power before they hit the rev limiter
I would think that the car was not revved to the rev limiter - ie the run was aborted as power dropped off
"Yes, why does it "give up" at around 6200 rpm?"
could be several reasons - but from what i've seen Nobles do not make big power at high rpm. It could be down to a restictive exhaust, cylinder head, exhaust housing, loss of boost, or just less ign timing at the top
to be fair most engines lose power before they hit the rev limiter
Edited by gadgeroonie on Thursday 23 November 19:57
gadgeroonie said:
the rpm signal was taken directly from the igniton system of the vehicle - it is accurate to 1rpm
I would think that the car was not revved to the rev limiter - ie the run was aborted as power dropped off
"Yes, why does it "give up" at around 6200 rpm?"
could be several reasons - but from what i've seen Nobles do not make big power at high rpm. It could be down to a restictive exhaust, cylinder head, exhaust housing, loss of boost, or just less ign timing at the top
to be fair most engines lose power before they hit the rev limiter
I would think that the car was not revved to the rev limiter - ie the run was aborted as power dropped off
"Yes, why does it "give up" at around 6200 rpm?"
could be several reasons - but from what i've seen Nobles do not make big power at high rpm. It could be down to a restictive exhaust, cylinder head, exhaust housing, loss of boost, or just less ign timing at the top
to be fair most engines lose power before they hit the rev limiter
Edited by gadgeroonie on Thursday 23 November 19:57
I thought an M400 rolls over at about 6250 but still makes power up till about 7000rpm
my guess is Gary has treated the car to some mechanical sympathy - its made peak power, there is no point revving it to the limiter on full throttle (unless that is what you want it to do !!)
its very unusual to see a car make its peak power right at max revs - I can think of one i ran recently - a turbocharged supra 853 hp and it was still making power !! we decided to not raise the rev limit, torque and boost had dropped off significantly and the owner would not realisitcally be changing gear up there.
its very unusual to see a car make its peak power right at max revs - I can think of one i ran recently - a turbocharged supra 853 hp and it was still making power !! we decided to not raise the rev limit, torque and boost had dropped off significantly and the owner would not realisitcally be changing gear up there.
gadgeroonie said:
my guess is Gary has treated the car to some mechanical sympathy - its made peak power, there is no point revving it to the limiter on full throttle (unless that is what you want it to do !!)
Looking at the before curve I guess he must have just cut it as it started to roll off the top of the curve but the limiter is around 7200 so I don't understand why it's cut so early. I'd want to know when it was worth changing up a gear and to do that I'd need to know how it tailed off from peak. Looks like you'd need to keep it between 4300 and 6000 to get the most out of it; keeping it between 4000 to 6000 is fine with the standard gearing but I'd still want to know what happens after 6200 ... have you got a leisurly change up or do you have to rush the change, in which case do you go into the corner a cog up, etc, etc.
Still, power-wise a definite improvement.
--
Richard
Thanks Mike and guys for the comments. Just hadn't got round to scanning anything...piled under with work.
I was wondering about the rpm range myself but I watched Gary doing some runs and he definitely lets up before the limiter while he looks at the curve being plotted live. Hence it was due to mechanical sympathy I feel...I agree no point going to the rev limiter on this car. Peak power/torque is likely to be below the actual rev limit. I normally change gear at around 6-6.5 k rpm anyway and use the car's torque rather than rev it to the red line every time. Similar to what I used to do with my Evo VIII MR...the best point to shift up in that was around 6.5k rpm even though the rev limiter was around 7.4k or so.
The car feels phenomenal...completely different to what it did prior to this result.
I was wondering about the rpm range myself but I watched Gary doing some runs and he definitely lets up before the limiter while he looks at the curve being plotted live. Hence it was due to mechanical sympathy I feel...I agree no point going to the rev limiter on this car. Peak power/torque is likely to be below the actual rev limit. I normally change gear at around 6-6.5 k rpm anyway and use the car's torque rather than rev it to the red line every time. Similar to what I used to do with my Evo VIII MR...the best point to shift up in that was around 6.5k rpm even though the rev limiter was around 7.4k or so.
The car feels phenomenal...completely different to what it did prior to this result.
ThatPhilBrettGuy said:
I'd still do at least one run up to the limiter to make sure the AFR doesn't go wonky up there. Best to know that if the red mist does come down it won't come clanking to a stop shortly afterwards.
Will do Phil...just as soon as I free up a bit. Will post that up too.
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