Mi16 Rolling Road Results

[taffycrook 2]

Monty could you explain that?

[VisaGTi16v 1]

Rolling roads measure at the road wheels, thats the only accurate figure. The estimated flywheel ones are then calculated on the coast down using the friction and various calculations. Every rolling road operator does it differently. I have seen people put up graphs where they had say 130bhp at the wheels and then 175 at the flywheel. Mine however was 142 at the wheels and 166 at the flywheel or 168 if I used the calculation on David Bakers website

[CaptainK 11]

My 1.2 Nova had 40bhp at the wheels, but strangely had 2000000bhp at the fly. All that just by adding my Max Power stickers.

 

I know of a few garages that deliberately overestimate the "at the fly" figures for "boy racer types" as it makes them feel better about their cars.

 

For a front wheel drive car, any more of a difference than 20-30bhp from "at the wheels" to "at the fly" and you know the operator is having a laugh.

[welshpug 1,621]

For a front wheel drive car, any more of a difference than 20-30bhp from "at the wheels" to "at the fly" and you know the operator is having a laugh.

 

not quite, the more power you have the more you will lose, unless you fit a more efficient transmission.

[bales 1]

i wouldnt take these estimated flywheel figures seriously lads. Its the wheel hp thats important and more accurate

 

But then again the at wheel figures can be skewed by just as much by having different tyre pressures etc....

[petert 549]

The estimated flywheel ones are then calculated on the coast down using the friction and various calculations. Every rolling road operator does it differently. [/url]

 

On DynoDynamics rollers it's not even that scientific. You just enter the multiplication factor you want! ie flywheel = wheel hp x 1.3

[VisaGTi16v 1]

That would give me 184bhp instead of 168 when talking down the pub

[C_W 3 1 Cars]

You'd be wrong. My previous engine (which blew) had a worked head, but this engine has a standard head with the cams. Standard pistons, liners, crank etc.

 

I would have thought it'd be impossible to get over 200bhp at just 6300rpm without a capacity increase?

[monty69 6]

Surely a decent operator would check tyre pressures before a power run. Theres so much bull going around with hp claims, id only take it as a estimate with a chassis dyno. ive no doubt there are a few dynos that are very accurate but everyone is using different so its a rough guide.Obviously a car with slimmer tyres, thinner oils and better transmision should give higher wheel readings but at least its measuring the chassis brake hp- what the car can do. My car was measured at 179 at fly, 143 at wheels- a big difference. It doesnt feel like 180hp, i used the puma calculation which gave me a much more believable estimate.

[Pugnut 9 1 Cars]

power is nothing without control. stick a 300bhp engine into a peice of s*it car and i can can gaurentee it'll still be a peice of s*it allbeit a fast one. I'de take lower bhp for a car that drives like its on rails and stops on a penny any day.

 

even down to the driver, i bet a professional driver could take my 205 and make it do thing i didnt think possible.

 

rollers should only be used as a guide for one person in one car who always uses the same rollers to judge whether modifications have made improvements and if the engine is healthy or not.

 

Al

[welshpug 1,621]

Surely a decent operator would check tyre pressures before a power run. Theres so much bull going around with hp claims, id only take it as a estimate with a chassis dyno. ive no doubt there are a few dynos that are very accurate but everyone is using different so its a rough guide.Obviously a car with slimmer tyres, thinner oils and better transmision should give higher wheel readings but at least its measuring the chassis brake hp- what the car can do. My car was measured at 179 at fly, 143 at wheels- a big difference. It doesnt feel like 180hp, i used the puma calculation which gave me a much more believable estimate.

 

a 35 bhp loss at that level of power is perfectly feasible through a standard BE transmission and driveshafts, its only a 19.5% loss.

[Mattsav 1]

Some RR's are so off its amazing. Even more amazing is that the owners/operators believe they are correct!!

 

We've seen a 65 bhp difference between a rolling road and the dyno on a Vauxhall Xe engine and seen claims for remapped engines where they think they are getting 30bhp more than the injectors can supply!

 

I've even argued with people when they honestly think they's got 200bhp from a 16v saxo with a set of '708 cams in a std engine. They'd just spent £50k on a dynojet and had it calibrated so it must be right!!

 

I've even seen very dubious results from engine dyno's!

 

VisaGTi16v's hit the nail on the head. There's power at the wheels, power at the fly and power at the Pub

 

As your in London, get it on Track and Road's RR near Dartford. They have an accurate RR and a no bullsh1t attitude.

[boldy205 74]

surely a RR set up is just that, a set up to make the car perform / run as well as it is capable of? When mine was setup i was intrested in knowing what the fly figure was, but once i got in it and started enjoying it i didnt care about figures. I just cared about doing the right thing, keeping scoobies at bay!!

[Rom 0]

Where did you have yours done Boldy ? Ive not lived in Bristol that long, so dont know many places.

I heard Interpro a few times, but also heard a lot of bad stuff.

 

Ive never got mine on the rollers since i built the engine, partly because im scared it will make rubbish figures,not so much because i want high figures..I just dont want to know i built a lemon !

[PVFCpug 6]

I would have thought it'd be impossible to get over 200bhp at just 6300rpm without a capacity increase?

 

You can see the printout, I agree that it is certainly different to my previous engine as that made 211@7.5k. The engine is a block and head from Pugtorque and all new inners from Peugout, all assembled by Neal @ DES. There is no capacity increase. The RR is a set-up for the carbs as opposed to a cock waving exercise. It is what it is.

 

I do not know how accurate the RR is but it's the one I have always used and has always been within 5% to the best of my knowledge.

[James_m 0]

Im starting to wonder if mi16's just dont really make the numbers. Certainly my own car does not really feel like its pushing 170ish bhp and comparisons with other cars bear this out. So not only can they not go round corners, they dont even make good power!

[welshpug 1,621]

my Mi16 DOES make the numbers (5bhp OVER std, froma std engine)

 

IMO its the same as the 8 valve engine, its all about a healthy injection/ignition system, and moreso on the 16v engine, having the correct valve timing.

[GLPoomobile 958]

I'm not sure how relevant these comments are, but I'll throw in my 2 cents worth.

 

My Mi16 was rebuilt by DES about 3 years back, when they did the conversion on the car (only covered a few thousand miles since). Not a proper, full on, 100% rebuild, more a comprehensive refresh I suppose (I'd need to dig out the receipt that came with the car to check). They included a RR printout from Hi-Tech or Hi-Tek, whatever the are called, but that one local to them that they use anyway.

 

The RR printout shows something like 145 bhp, and drops off abrubtly at about 6.5k. If that's the wheel bhp figure, I'd say it's way optimistic (standard Mi), which I have heard is the case with this particular RR, although I've also heard that they always give the fly bhp reading. But if it's the fly reading then I'd be a bit pissed that I'm 15bhp down.

 

When I got the car I thought it was quick, but not stunningly so. I did notice on one moment of stupidity that it wouldn't go beyond 120 leptons. Shortly after that the AFM died. When I swapped the AFM for a working one I found the car much faster - the sort of pace I'd expect from an Mi on a 1.6 'box, and the sort of pace I'd experienced in another Mi. Performance at stupid speeds was now in a different league.

 

So basically, I have no idea what my engine output is. I'm curious, but it's not the be all and end all. All I know is that my Mi is as fast as I'd expect it to be, and once I get it back on the road I can go back to enjoying that. I'm very doubtful that it is 'only' 145 bhp as the performance is far greater than either my 1.6s or 1.9. I do hope it's got roughly it's full quota of factory ponies left, but like I said, I don't want to get hung up on figures.

Edited August 3, 2008 by GLPoomobile