Evora Power

[Mikie711]

So today I had my Evora rolling roaded to get a base line before any mods are done and out of pure curiosity.
We used 22% for transmission loss which may be a bit high. If you compare wheel power to Lotus quoted then you get 14% losses or thereabouts which is definitely to low. So the truth is somewhere between the two. Top line is calculated flywheel power, bottom actual wheel power. No tyre slip, big back wheels and the V6 lump take care of that happening.
Standard NA car with Lotus Sports back box. 3.5k miles.
Good torque figures though
WHP 241bhp
Fly Wheel HP 293bhp (calculated)
Torque 291 lbs/ft

[C7Steve]

Are the figures close to what you were hoping for?

What mods are you thinking of doing?

[tut]

Mike, does Ricky's measure WHP?

I thought it would have been flywheel power as it is not a chassis dyno.

tut

[Mikie711]

tut, you kinda got that the wrong way round. It's not an engine dyno it is a chassis dyno. He has got himself a newer one since last time you were out at his. And all rolling roads, without exception read wheel HP. There isn't a rolling road in the world that reads flywheel HP. For that you need an engine dyno.
Steve, maybe a new exhaust in the pipe line.

[tut]

What about the ones that clamp onto the rear wheel Mike, are they not different?

tut

[Mikie711]

Hub dyno clamps on in place of the wheel there advantage is that you don't loose power through the tyre. Readings will still be less due to transmission looses though.

[Mikem7709]

I would've thought 15% transmission loss would be maximum for a manual MR layout ? Most places use 12-15% loss for an Exige/Elise. 22% is what I would expect from an old 4WD set up, most modern manual FR cars don't loose more than 15%.

I guess The important thing is to work off the WHP figures on the same dyno in simillar conditions to get a true picture of what the mods have achieved.

[Scuffers]

I would've thought 15% transmission loss would be maximum for a manual MR layout ? Most places use 12-15% loss for an Exige/Elise. 22% is what I would expect from an old 4WD set up, most modern manual FR cars don't loose more than 15%.

agreed

Transverse FWD gearboxes are ~7-10% these days, + a bit for the tyres, 15% would seem more realistic.

[Mikie711]

As I understand it the majority of the losses are not so much through the gearbox but through the tyres. There is a research place in Switzerland that has done about 600 comparison runs between engine and chassis dyno's and they recon the average loss is about 17% for rear wheel drive. But it's arbitrary as mentioned the figure to use is WHP, realy torque at the rollers if we're being pedantic, as that will reflect any changes.

[H8OAG]

Hi Mike
One of the young blades down in Slough Office has an Evora with a fancy exhaust.............very loud (Supersprint?)

[Mikie711]

More to follow on the "exhaust" in a couple of weeks

[C7Steve]

More to follow on the "exhaust" in a couple of weeks

2ubular special?

[Scotty C]

http://www.komo-tec.com/product_info.ph ... ts_id=669&

[Rosssco]

You're probably aware of this, but the guys fitting 2GR-FE engines into MR2's, get very good results from improved manifold and y-pipe designs. Not sure on fitment and suitablity (no cats) on an Evora though...

[Mikie711]

http://www.komo-tec.com/product_info.ph ... ts_id=669&

Think I will keep my €3690 for worthwhile upgrades. Expensive 30 bhp.

You're probably aware of this, but the guys fitting 2GR-FE engines into MR2's, get very good results from improved manifold and y-pipe designs. Not sure on fitment and suitablity (no cats) on an Evora though...

Watch this space