Transmission Losses

[Guest Doc883]

I was quoted by a company that their tuned 1.9 (original 128 bhp) that gave a "quoted" 160bhp would be 120bhp on a rolling road thus allowing for a 33% transmission loss, is this correct ?

[inferno 1]

I was quoted by a company that their tuned 1.9 (original 128 bhp) that gave a "quoted" 160bhp would be 120bhp on a rolling road thus allowing for a 33% transmission loss, is this correct ?

iirc my mi16 making 169 was said to have 130 at the wheels. but there was a big debate as to the accuracy of the loss calculations, 130 i think was acceptable but 169 on a standard looking engine was not...

[Pugnut 9 1 Cars]

iirc 15-17% is about right for a fwd car .

 

33% is just fudging the figures to make you think it has lots of ponies at the flywheel. you've been told a crock of s*ite i'm afraid.

 

should be more like 138 bhp at the flywheel , Although if they have have told you to add 33 percent losses then the bhp figure is probably a load of crap too.

 

 

 

Al

 

 

(OMG a rolling road topic !!! run for you're lives...........................)

[Pugnut 9 1 Cars]

just to add , if it does give a true 120 at the wheels it's still a pretty good tuned 1.9.

[Guest Doc883]

iirc 15-17% is about right for a fwd car .

33% is just fudging the figures to make you think it has lots of ponies at the flywheel. you've been told a crock of s*ite i'm afraid.

should be more like 138 bhp at the flywheel , Although if they have have told you to add 33 percent losses then the bhp figure is probably a load of crap too.

Al

(OMG a rolling road topic !!! run for you're lives...........................)

Cheers Al, thought as much and good job I cancelled the car. They were unable to provide a rolling road printout, no printer apparantly, and were simply going to show me the figures whilst on the rolling road.

[GLPoomobile 958]

Just think, if you lose 33% in a FWD car, how much would you lose in a 4WD car?!!!! That 300bhp Evo ain't gonna be too impressive when it's only putting out about 150bhp at the wheels is it!

 

Bloody charlatans.

[Sandy 191]

Charlatans can't be blamed for this, their unique style of nasal indie pop doesn't affect the results, in fact they penned "How high" as a protest against inaccurate rolling road figures.

[Mattsav 1]

Charlatans can't be blamed for this, their unique style of nasal indie pop doesn't affect the results, in fact they penned "How high" as a protest against inaccurate rolling road figures.

 

 

[V8Pete 0]

My 130 hp GTI got 88 hp on the dyno recently. I've heard that's slightly on the low side of normal for them though, but would be 32% down if it was actually producing 130.

[GLPoomobile 958]

Charlatans can't be blamed for this, their unique style of nasal indie pop doesn't affect the results, in fact they penned "How high" as a protest against inaccurate rolling road figures.

 

 

No I honestly did mean The Charlatans! They get blamed for everything in my household! Bloody Mancs

[Ahl 4]

My 130 hp GTI got 88 hp on the dyno recently. I've heard that's slightly on the low side of normal for them though, but would be 32% down if it was actually producing 130.

Either the rolling road isn't right, or it is right and the cars only making 108hp or so. 33% transmission loss is nonsense.

 

I was quoted by a company that their tuned 1.9 (original 128 bhp) that gave a "quoted" 160bhp would be 120bhp on a rolling road thus allowing for a 33% transmission loss, is this correct ?

Lmao! Which company was this btw? I know Ecosse quote something stupid like that, but thats only because their rolling road gives out silly figures.

[WildCards 0]

33% is balls.

 

My VR4 with auto box, torque converter, AWD system etc only made 172bhp at the wheels and a calculated 243bhp ATF on a very reputable dyno which equates to about 29% loss. I'd expect something like 20% max.

 

Don't Ecosse have a downhill rolling road?

 

/EDIT - Puma Racing site - http://www.pumaracing.co.uk/PUG2058V.htm - states 'the rules I use for equating flywheel and wheel bhp on front wheel drive cars. The simple equation is to deduct 15% from the flywheel bhp and the longer version is deduct 10% plus a further 10 bhp.'

Edited February 28, 2007 by WildCards

[welshpug 1,657]

My 130 hp GTI got 88 hp on the dyno recently. I've heard that's slightly on the low side of normal for them though, but would be 32% down if it was actually producing 130.

 

but they were never quoted as being 130, its a common myth, the published figure was 128

makes you feel a little better that theres 2bhp less to account for

 

 

my engine power was recently calculated at 121.8 bhp, with 78.3 at the wheels, so 43.5 bhp loss but I know my gearbox is knackered.

[WildCards 0]

Only ever rely on the wheels figure as that is the only one that is accurate. Any operator can fudge the figures to look like it's right.

[Emmy Seize 8]

30 % ish seems about ok for a standard car.

 

I had a car with a new camshaft on the dyno, the cam was supposed to give an extra 10 PS on top of the standard output of 130 PS.

 

The at the wheels figure was 96 PS meaning 31 % loss.

 

Be careful with percentages anyway: Transmission loss is a static thing, loss in percentage is not.

 

On a tuned engine, loss in percentage must be lower than on the standard car.

 

Everything else would imply that transmission losses grow with increasing power output.

 

Which is nonsense, of course.

[Batfink 201]

30% loss in fwd would make me cry. 4wd would have about 50%!

I know that if I used 30% rule my mi16 on throttlebodies would be estimated at 190bhp but I know thats not true. Using puma's formula it has a more realistic 176bhp

[Normski 1]

Only ever rely on the wheels figure as that is the only one that is accurate. Any operator can fudge the figures to look like it's right.

I've just read an article in PPC magazine about rolling roads written by Dave Walker and he says the exact opposite of the above. The at the wheels power figures can be changed by altering the tyre pressures, different size tyres and running in different gears.

[Guest Doc883]

Lmao! Which company was this btw? I know Ecosse quote something stupid like that, but thats only because their rolling road gives out silly figures.

It was the LAD's in Morecambe who quoted me 33% and after all they have x number of years in Motorsport

[petert 586]

I've just read an article in PPC magazine about rolling roads written by Dave Walker and he says the exact opposite of the above. The at the wheels power figures can be changed by altering the tyre pressures, different size tyres and running in different gears.

 

But where do you think the flywheel figure comes from?

 

Power is transmitted through the wheels to the dyno. All you can do is measure the force transmitted by the tyre to the roller. Then use a computer to turn the number into something meaningfull.

 

The best you can do is hope to go home from the dyno with more than what you started with.

Edited March 3, 2007 by petert

[Richie-Van-GTi 71 2 Cars]

It was the LAD's in Morecambe who quoted me 33% and after all they have x number of years in Motorsport

 

 

Im sure if you do a few searches on their 160bhp conversions you will find all the info you need.

My 205 apparently had this conversiuon with recipts to prove, LAD stamped in head etc. It made 92bhp ATW on rollers which equates to around 118 at the fly according to the rolling road operator. The operator is known and trusted by many people in the north east and I have no reason to disbelieve the figures. the car was also running a bit lean and he reckoned with an adjustable reg I could of gained another 7-8bhp. Either way, a long way short of 160bhp. Did they offer you a special french cam? I took mine out and found it to be a special cam from france.....made by PSA in a limited number......limited to number of pug 1.9's + spares

[Ahl 4]

LAD explains a lot, interesting that your car didn't even make standard power Richie.

 

I guess 33% transmission loss on their '160hp' conversion would you give a standards car 108hp at the wheels.

[Rob Thomson 6]

When I was young and niave I let LAD do their 160bhp conversion to my trusty old 309. It was significantly slower afterwards (0-100mph in 30secs!!) and drove like a bag of s*it. In addition it used about 2 litres of oil per 1000 miles. In short they completely f***ed it up. Whenever I spoke to them about it it was never their fault, always something I had done to the engine. The paperwork was extremely vague so I had no real comeback. I wish I'd been a bit older and more prepared to tell them to f*** off and die.

 

Ernie, if you want to take me to court for saying that your work is s*it please feel free.

 

Edit: Mine showed 120bhp at the wheels on their rollers, which they said is what a standard Mi16 shows, hence the 160 claim. But there is no way that mine produced 120bhp at the flywheel, let alone at the chuffing wheels.

Edited March 3, 2007 by Rob Thomson

[PumaRacing 2]

I was quoted by a company that their tuned 1.9 (original 128 bhp) that gave a "quoted" 160bhp would be 120bhp on a rolling road thus allowing for a 33% transmission loss, is this correct ?

 

With three posts to your credit I guess you're fairly new to Peugeot tuning and maybe all tuning. I suggest you start out by reading the various tuning articles on my website including the 2058v and the "160 bhp scam" section. I'll leave you to work out what it refers to.

 

Once you've got a better idea of what is realistic you'll be less likely to get ripped off.

 

160 bhp without carbs or throttle bodies, big valve head and/or rally cam is just not possible. If you think anyone can add 40 bhp (yes 40 because the std engines only put out about 120) with a bit of porting and the same cam you drove in with you need to do more research.

 

A 160 bhp LAD conversion a customer had independently tested showed 108 at the wheels. That's about 131 flywheel and maybe 10 up on std. That's exactly what you'd expect from a bit of headwork. I've driven others and a colleague has had 10 or 12 pass through his hands. They all drive the same. Usually not for long though.

 

If you want some realistic figures, all from Mikanics rollers in Cheshire, there are several to choose from.

 

BV head, 11:1 cr, exhaust and manifold, Catcam 340 (255 degrees duration) , std injection - 150 flywheel bhp (someone on this forum)

 

BV head, 11:1 cr, exhaust and manifold, Kent PT27 cam (267 degrees duration), std injection - 158 bhp flywheel bhp (someone not on this forum)

 

BV head, 11:1 cr, exhaust and manifold, Catcam 340, Throttle bodies - 166 flywheel bhp (someone on this forum)

 

BV head, 11:1 cr, exhaust and manifold, Kent PT27 cam, 45mm carbs - 173 flywheel bhp (someone not on this forum) Hopefully some graphs for this one will be appearing soon.

 

The bigger Kent PT27 cam is worth 8-10 bhp over the milder Catcam 340 but with loss of low rpm tractability. Without the sort of spec above you'll never get anywhere near 160 bhp though.

[brianthemagical 1]

Be careful with percentages anyway: Transmission loss is a static thing, loss in percentage is not.

 

i tought trany losses (friction and inertia i think getting the power from the engine to the wheels) is proportional to the power. if your putting more power in to turn the rollers then equal and opposit andf all that and the there will be more stress on the components, like wheels and gears in 'box.

 

please correct me if i'm wrong but it seemed logical to me.

[Richie-Van-GTi 71 2 Cars]

makes more sense to me that transmission loss is closer ot be a fixed value as surely once you pass the point of inertia on the various components involved the loss would be negligble.

 

PS, I think my car would of made the standard power had the pump and reg been up to the job. about 6 weeks after the rolling road my pump showed massive signs of failing (no power above 3k rpm) and 1 milelater it would do little more than idle. RAC truck home that day!!

Edited March 4, 2007 by Richie-Van-GTi