Mark Adams choise ?
Discussion
Not sure which run that was; they were all amost identical. The other two TVRs were treated similarly. Was it unusually short ?
The fluffing around before the power is really turned on is where 3rd gear refused entry. It does that sometimes. I always double declutch these days, it's better than missing a gear when it really counts.
The fluffing around before the power is really turned on is where 3rd gear refused entry. It does that sometimes. I always double declutch these days, it's better than missing a gear when it really counts.
I had my car (400SE) on the rollers at Interpro in Thornbury (nr Bristol) in March this year, and made 256BHP @ 5700RMP at the flywheel with 63BHP transmission drag (that’s 193 at the wheels for those without calculators !) Stock engine apart from ACT Carbon trumpet base.
That’s still pretty hot for a 4.0 rover lump.
I am building a 4.5 engine at the moment + supercharger, (using 'Stump-Puller' cam BTW) but even then I don't expect to achieve anything close to 281 at the wheels, because I would need to be looking for 344BHP at the flywheel, and that’s scorching, even for a 4.5 with a very hot cam!
Conclusion..., either the Dyno that measured the 281BHP figure was out, or you have something other that a mildly tuned 4.0 under the bonnet ! I hope it’s the latter, because with that sort of power you could suck the doors of a 5.0 Griff.
That’s still pretty hot for a 4.0 rover lump.
I am building a 4.5 engine at the moment + supercharger, (using 'Stump-Puller' cam BTW) but even then I don't expect to achieve anything close to 281 at the wheels, because I would need to be looking for 344BHP at the flywheel, and that’s scorching, even for a 4.5 with a very hot cam!
Conclusion..., either the Dyno that measured the 281BHP figure was out, or you have something other that a mildly tuned 4.0 under the bonnet ! I hope it’s the latter, because with that sort of power you could suck the doors of a 5.0 Griff.
quote:
Conclusion..., either the Dyno that measured the 281BHP figure was out, or you have something other that a mildly tuned 4.0 under the bonnet ! I hope it’s the latter, because with that sort of power you could suck the doors of a 5.0 Griff.
Hey dont dis the messenger ... Im only telling what the dyno showed ... If the dyno is out, then I accept that., thats why I said that I dont have anything to quantify the results with. Richard Aldous was there as a whitness.
Incidently, When the car was first obtained by me, it showed 179 at Interpro (It was the closest Dyno to me)
quote:I don't think that this is that far off - see www.pumaracing.co.uk/trans.htm (he provides the maths to prove his point)
That implies a loss of only 12% through the transmission, which seems unbelievably low. Just as 320 from a 4.0 Rover with minor mods seems unbelievably high. Let's see the dyno chart & type.
The article reckons that transmission losses of 12% + 10BHP are typical of a RWD car & that most rolling roads overinflate the power at the flywheel figure
cheers,
Craig
quote:
quote:
Conclusion..., either the Dyno that measured the 281BHP figure was out, or you have something other that a mildly tuned 4.0 under the bonnet ! I hope it’s the latter, because with that sort of power you could suck the doors of a 5.0 Griff.
Hey dont dis the messenger ... Im only telling what the dyno showed ... If the dyno is out, then I accept that., thats why I said that I dont have anything to quantify the results with. Richard Aldous was there as a whitness.
Incidently, When the car was first obtained by me, it showed 179 at Interpro (It was the closest Dyno to me)
Hey, don't get stressed, I'm not doubting the results that you have, just offering some alternative explinations for such a good result.
The best way to qualify any dyno result is how the car actually drives. I like to go to Santa Pod myself, level playing field, best time wins, simple...!
Anyone got some quarter mile times for their wedge ?
The search for the absolute BHP figure is a difficult one. Most of the dynos I use give slightly different results.
John Eales and V8 Developments engine dynos agree with each other, and Power Engineering's rolling road shows roughly the same numbers.
However the Mech Repairs rolling road shows similar wheel figures to Power Engineering, but almost 50BHP less flywheel on most motors. The method of calculating the losses seems to vary with rolling roads.
This means it is best to stick with one dyno for your development project, and only worry about the relative increments.
Phil - I don't know how far you have got with your supercharging project, but it may be worth us having a swift chat. I've done about fourteen of them now, and I have lots of useful info about what works best and how to set it up. I have the management side fully sussed (even with catalysts) up to one Bar, and good initial maps etc.
As I have learned (the hard way) you don't get a second chance with forced induction. If it's wrong you get liquid pistons!
Maybe you don't need any help which is OK too, so please forgive me for poking my nose in if it isn't welcome!
As a result of the turbo and supercharging work done in conjunction with V8 Developments, they have special heads and cams developed and available. There are a few tricks to getting the most out of your cam timing etc.
Anyway it sounds like fun - please keep us all posted with how you get on.
John Eales and V8 Developments engine dynos agree with each other, and Power Engineering's rolling road shows roughly the same numbers.
However the Mech Repairs rolling road shows similar wheel figures to Power Engineering, but almost 50BHP less flywheel on most motors. The method of calculating the losses seems to vary with rolling roads.
This means it is best to stick with one dyno for your development project, and only worry about the relative increments.
Phil - I don't know how far you have got with your supercharging project, but it may be worth us having a swift chat. I've done about fourteen of them now, and I have lots of useful info about what works best and how to set it up. I have the management side fully sussed (even with catalysts) up to one Bar, and good initial maps etc.
As I have learned (the hard way) you don't get a second chance with forced induction. If it's wrong you get liquid pistons!
Maybe you don't need any help which is OK too, so please forgive me for poking my nose in if it isn't welcome!
As a result of the turbo and supercharging work done in conjunction with V8 Developments, they have special heads and cams developed and available. There are a few tricks to getting the most out of your cam timing etc.
Anyway it sounds like fun - please keep us all posted with how you get on.
I think its always best to read power at the road wheels as this tends to be more consistent. as a guide standard 4.0L griffs are about 160-165 400SE's are 175-180, 5.0L are 210-220, It does n't really matter what the flywheel figure is, because they all tend to vary, if you have a wheel figure much less than this there may be a problem with the engine.
To go back to the original question, I agree with Mark totally, The latest Kent Cams have a slightly better idle now, V8 Developments do a new cam that replaces the Kent 218 code named MC1 i haven't used it but sounds bloody good, idles better and still offers the same overall power.
Tim
To go back to the original question, I agree with Mark totally, The latest Kent Cams have a slightly better idle now, V8 Developments do a new cam that replaces the Kent 218 code named MC1 i haven't used it but sounds bloody good, idles better and still offers the same overall power.
Tim
quote:
Hey, don't get stressed, I'm not doubting the results that you have, just offering some alternative explinations for such a good result.
The best way to qualify any dyno result is how the car actually drives. I like to go to Santa Pod myself, level playing field, best time wins, simple...!
Anyone got some quarter mile times for their wedge ?
Im not stressed
im up for a santapod session soemtime. Last time I Timed a standing quarter sing the police markers on some dual carrageways (at night!) ) Mine was a very inacurate 13 1/2ish seconds. My best 0 - 60 time achieved was a shade under 5 seconds (again, warm dry night, passenger with stop watch ) If there is enough interest .... lets do it.
quote:
Im not stressed
If there is enough interest .... lets do it.
The next Run What Y' Brung day at the Pod is Sunday 6th October. I'll be there (If its dry !).
Anyone else....?
Right, Took the car down to Peninsula for its MOT on Saturday Morning, and persuaded Richard Smith to take me to a local Rolling road.
WE put the Wedge on the rollers, no setting up, or tweaking at that time, and performed a few power runs.
The figures we obtained from the second I must say are very encorouging, and even Richard was suprised to say the least.
The end figure of 202bhp at 5500rpm was obtained. The dyno did show a higher figure of between 215 and 220 but the needle didnt settle down, so, see-ings that the car had been standing stale for the last 6 months, and Richard's time was limited, we decided to take this figure.
The guy who owns the rolling road normally builds Rally cars, and, in taking into account things like transmission losses, differential oil viscosities and other highly technical stuff ( mean air pressure etc etc etc ) gave a nominal figure of between 55 - 80 bhp loss through the Transmission and gearbox.
Richard was very much encouraged by these figures, and went on to explain that on Tasmin Racers etc, he usually see's 130'ish at the wheels, and on a 4.0 Chimp that had been done a few weeks previously, a figure of 175-180 at the wheels was obtained.
For the purests out there, the road was re-calibrated in August this year following flooding of the premises.
So .... with these figures as a guide, what happens next ?
A Mark Adams Chip ?
Bigger Airflow Meter / Remap ?
Stage 3/4 Heads ?
New Stainless Exhaust Manifolds ?
A nice Carbon Plenum ?
A set of Trumpets ?
I was planning a bigger engine, but I t5hink Ill just make the one I currently have a little better!
WE put the Wedge on the rollers, no setting up, or tweaking at that time, and performed a few power runs.
The figures we obtained from the second I must say are very encorouging, and even Richard was suprised to say the least.
The end figure of 202bhp at 5500rpm was obtained. The dyno did show a higher figure of between 215 and 220 but the needle didnt settle down, so, see-ings that the car had been standing stale for the last 6 months, and Richard's time was limited, we decided to take this figure.
The guy who owns the rolling road normally builds Rally cars, and, in taking into account things like transmission losses, differential oil viscosities and other highly technical stuff ( mean air pressure etc etc etc ) gave a nominal figure of between 55 - 80 bhp loss through the Transmission and gearbox.
Richard was very much encouraged by these figures, and went on to explain that on Tasmin Racers etc, he usually see's 130'ish at the wheels, and on a 4.0 Chimp that had been done a few weeks previously, a figure of 175-180 at the wheels was obtained.
For the purests out there, the road was re-calibrated in August this year following flooding of the premises.
So .... with these figures as a guide, what happens next ?
A Mark Adams Chip ?
Bigger Airflow Meter / Remap ?
Stage 3/4 Heads ?
New Stainless Exhaust Manifolds ?
A nice Carbon Plenum ?
A set of Trumpets ?
I was planning a bigger engine, but I t5hink Ill just make the one I currently have a little better!
jvaughan said:
The end figure of 202bhp at 5500rpm was obtained.
So .... with these figures as a guide, what happens next ?
A Mark Adams Chip ?
Bigger Airflow Meter / Remap ?
Stage 3/4 Heads ?
New Stainless Exhaust Manifolds ?
A nice Carbon Plenum ?
A set of Trumpets ?
I was planning a bigger engine, but I t5hink Ill just make the one I currently have a little better!
Now that's more like it ! (79 BHP down on your initial reading of 281 BHP). Still, a 400SE in good shape.
What to do next..., Supercharge it..., you know it makes sense.
To follow on from my previous email, below ate the bhp results with the rpm obtained from my session on the rollers
RPM BHP LB-FT
0 0 0
1000 30 158
1500 48 168
2000 67 176
2500 90 189
3000 115 201
3500 144 216
4000 168 221
4500 188 219
5000 200 210
5500 202 193
6000 200 175 (guessed)
Many thanks to Peter Humphries for the Torque figures
>> Edited by jvaughan on Wednesday 16th October 15:00
RPM BHP LB-FT
0 0 0
1000 30 158
1500 48 168
2000 67 176
2500 90 189
3000 115 201
3500 144 216
4000 168 221
4500 188 219
5000 200 210
5500 202 193
6000 200 175 (guessed)
Many thanks to Peter Humphries for the Torque figures
>> Edited by jvaughan on Wednesday 16th October 15:00
jvaughan, are they bhp at the wheels? If so the torque figures need to be corrected for the loss through the transmission. If you allow 12% + 10 bhp for losses you will not be far out.
Thus 90 bhp at 2500 = a real 112 at the flywheel therefore gives a torque figure of 235 (which is more realistic in my opinion).
So 200 at 5000 = 237 bhp and 249 lbs/ft torque.
Thus 90 bhp at 2500 = a real 112 at the flywheel therefore gives a torque figure of 235 (which is more realistic in my opinion).
So 200 at 5000 = 237 bhp and 249 lbs/ft torque.
jvaughan said: Peter Humphries did the Torque calculations for me, based on, I assume his own experience in the V8S.
All the figures were "at the wheels"
As a matter of extreme interest to any anoraks out there. the calculation goes like this
Torque X RPM divided by 5252= BHP, so if you have one you can work out the other.
I'll get me vinyl coat !!
Tim
the calculation goes like this
Torque X RPM divided by 5252= BHP, so if you have one you can work out the other.
Rats, I was using 5250!
Torque was calculated directly from the supplied BHP, so if the power was at the wheel, so was the torque. If you're subtracting transmission losses, you'll have to apply it to *both* sets of figures.
Cheers
Peter Humphries (and a green V8S)
Gassing Station | Wedges | Top of Page | What's New | My Stuff