Reading all the very interesting threads on various engines and upgrades, I wonder just where my VHPD 190 is on the BHP scale. Following numerous questions, it seems that the 190 ‘upgrade’ VHPD may produce anything from 170ish BHP to 200 ish BHP…
Was going to enquire about Emerald and Verniers, but little point untill I can work out where mine is now. It may be at either end of the scale (Top end I hope!!!)
SO… where do you recommend the best (safest!) place is to get a good dyno test and result as a starting point? And do you think the whole idea of Dyno testing is really such a good idea anyway… stress on engine/water/oil cooling issues etc etc?
Pete, have you joined MLOC yet ? We’re due to have a rolling road day soon. In the past we’ve been to Aldon, south Birmingham, but with several recent cars with conversions, we might go somewhere with a rolling road capable of more than 250bhp.
The important point is to use the same place and operator for the before and after modification tests.
Just consider a power run to make sure that there are no real bad suprises - and no a RR session shouldnt put a great strain on the engine, it just sounds that way cos you not usually so close to your car doing 100 mph and 8000 rpm
Andy makes a good point about before and after tests, however when we do the MLOC rolling road, there’s likely to be a few cars there that have done previous RRs and we would therefore have a good yardstick comparing Elises and Exiges.
The Aldon RR tended to underestimate cars around 200bhp but, importantly, all the S1 Exiges were at about the same figure. I think a couple have also been measured elsewhere as well.
Can’t see the point of dyno runs, unless you’re having the car properly mapped, or it’s on the same day as fitting a different exhaust or induction kit etc. Just too many variables, & if you really want to max the bhp printout, just use 2nd gear, & drop the tyre pressures by 5psi (as recommended by a certain Dave Walker).
You need to up the tyre pressures to raise the ‘at the wheels’ figure, that way the tyres deflect less and the losses are lower. On a rolling road that does a coastdown test there will be no difference.
If you can get your RR run on an accredited RR where other Exiges have been run then you will have a useful comparison and yardstick.
You need to up the tyre pressures to raise the ‘at the wheels’ figure, that way the tyres deflect less and the losses are lower. On a rolling road that does a coastdown test there will be no difference.
If you can get your RR run on an accredited RR where other Exiges have been run then you will have a useful comparison and yardstick.
Dave
I’ve spent days on rr dynos and have never seen any difference in readings with different tire pressures, trust me I’ve tried after learning about that here…Stock NA Exige = 160 rwhp
Can’t see the point of dyno runs, unless you’re having the car properly mapped, or it’s on the same day as fitting a different exhaust or induction kit etc. Just too many variables, & if you really want to max the bhp printout, just use 2nd gear, & drop the tyre pressures by 5psi (as recommended by a certain Dave Walker).
Hi Mr Pesky!
Saw your car a few weeks ago at chez Edwards… I now have glasses too! AMAZING!!!
My desire for a dyno run followed chats with Emerald 3D regarding poss of fitting verniers and Emerald ECU. No point came the reply, untill you know where you are on the BHP front, ie: if yours is making lots of good drivable power…which 'I think (hope)! mine VHPD is, then any mods and money spent may leave me disappointed!
So just want to get the VHPD yardstick done… and then I will see where I am!
Yes I am also a member of MLOC, so would really appreciate further info on the ‘local’ dyno and the up-soming testing day!
That depends if the dyno has a coast down test, if so then there will be no difference.
It is well know that the rolling resistance of an underinflated tyre is far higher then that of a tyre that is overinflated, it is this rolling resistance magnified by the fact that the rollers present two contact patches of much smaller radius than the road surface that causes the losses to be much higher with underinflated tyres. If your rolling road reads the same with 5PSI and 80PSI then it’s time to buy a new one.
I have seen this proven time and time again on the rolling road.
I think everyone on this forum would be staggered if the fitting of an Emerald ECU & verniers didn’t improve the power output (over the Lotus ECU), & just as importantly, the overall driveability of your car.
I suppose that in an ideal world, you’d take your car to Emerald, do a run, & then let them fit the ECU & verniers, while you wait
No, that would be daft , but it is just a case of stretching a point to make a point, there are material differences even when tyre pressures vary between… say… 25 PSI and 35PSI, also roller speed and therefore the gear that the run is taken in make a marked difference because the rate of the tyre compressions is higher when roller speed is higher.
To get the best at the wheels figure overinflate the tyres and take the run in the lowest gear you can.
As I have no personal knowledge of the Emerald, you may well be right but I am (or was when dyno tested) getting 187bhp out of a standard Lotus 190 ECU and pulleys, so Emerald would be a very expensive way of liberating an extra few bhp, even if there were there to be had.
I haven’t had a chance to do much tuning on an NA car but what I’ve seen so far there is at least 15rwhp with CAI, header and cat delete exhaust with proper tuning…