MR2 Roadster Owners Club

The Workshop => Performance Related => Topic started by: Anonymous on July 27, 2006, 13:26

Title: £1000 per bhp!
Post by: Anonymous on July 27, 2006, 13:26
Just got back from Millways. Got the PPE header, downpipe, H&S exhaust, Markiii inlet pipe and Unichip. Expected to be getting at least 155bhp.....

139bhp   s:( :( s:(   and 132lbft   s:? :? s:?  

It's a very hot day and power run was done after 1.5 hours tuning on the rolling road, so the engine bay was scorching but that is pathetic!   s:shock: :shock: s:shock:  

I was thinking either my engine is knackered, or the dyno was massively under reading. The Millways man did say that MR2 roadsters normally get about 120bhp on their rollers! Is that true anyone?

It does feel a bit quicker to drive. Bit more torque.

Any ideas?

Think i'll go out and try the GTech and see what figures I can get.
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Post by: Two's Company on July 27, 2006, 13:31
I got 146 bhp on Millways Dyno with Unichip, TRD filter, Inlet pipe, gutted pre cats and TTE exhaust.

Roger got the same IIRC with similar mods.   s:? :? s:?
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Post by: spit on July 27, 2006, 13:39
That was at WRC wasn't it Steve? Or am I being thick today?

Dynos do vary. WRC is considered more "true" because of its ability to accurately reflect the loadings of a normal road - which is why it tends to read a bit lower than some other dynos.....

.....at least thats what I was told!

Matt. Is your reading at flywheel or at the wheels? How does it feel with the butt-dyno?  s:wink: :wink: s:wink:
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Post by: Anonymous on July 27, 2006, 13:39
Sounds like their dyno under reads..... (I hope)   s:? :? s:?

I asked, and they said at the flywheel.

What's a butt dyno   s:oops: :oops: s:oops:
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Post by: roger on July 27, 2006, 13:53
I got 150 @ Millways (with precats)

(http://static.flickr.com/9/15328353_a90d88ac0a_m.jpg)

The lower reading as mentioned by Steve was at WRC, IIRC I think I was a bit below that. Low 140s I think.

Butt dyno....by the seat of your pants, does it feel better / quicker etc?
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Post by: Anonymous on July 27, 2006, 13:58
Quote from: "roger".....Butt dyno....by the seat of your pants, does it feel better / quicker etc?

Feels a bit quicker, especially putting my foot down at 70mph in fifth (on private roads of course   s:wink: :wink: s:wink:  )
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Post by: roger on July 27, 2006, 13:59
Just another thought Matt, did they give you a before and after like above?

If so, I reckon its the difference thats important, rather than absolutes.
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Post by: Anonymous on July 27, 2006, 14:03
No before and after   s:cry: :cry: s:cry:
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Post by: GSB on July 27, 2006, 14:20
Dyno numbers mean nothing...

Repeat for the hard of understanding, NOTHING

Forgive me if I'm being a little short here, but this is such a common misunderstanding, and I dont have time at the moment to explain things fully.

A rolling road dynamometer is an indicative tool only, it is not, and never can be, an absolute guage of power. Its primary use in tuning is to be able to apply repeatable loads to an engine so that fine adjustments can be carried out. A dyno operator is rarely interested in the actual numbers, but weather those numbers go up or down when he makes an adjustment. And thats the whole point. Its a tool that provides data as to weather the amount of force being applied to the rollers is more or less than it was moments ago prior to an adjustment being made. If the number at the end is bigger when you leave the dyno than when you arrived, then be happy. If the car feels better to drive, be happy, if the number is disapointing, ignore it, as 9 times out of 10 its wrong anyway...

The key is not the number, but the difference between the numbers before and after the change. If you dont have the numbers before the changes, you cant make any kind of judgement.

Just for reference, I once dynoed my car on a day like today, when it was scorching hot, and got 112 bhp on a dyno that had previoulsy read 140bhp on a cooler day. Engines dont like hot air.
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Post by: Anonymous on July 27, 2006, 14:38
That's the stuff. I feel better now.   s:) :) s:)  

Yeah, numbers mean nothing. It drives better and that's all that counts   s8) 8) s8)
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Post by: Anonymous on July 27, 2006, 14:39
Besides, it's cheaper to insure if it's only gained 1bhp   s:wink: :wink: s:wink:
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Post by: Two's Company on July 27, 2006, 15:00
Quote from: "spit"That was at WRC wasn't it Steve? Or am I being thick today?

The dyno was 146 bhp at WRC and Millways.  As Grant says the figures don't mean that much, at Millways it produced 157 bhp on the run before the Unichip and 146 after but it felt much better after so I was happy.   s:wink: :wink: s:wink:  

Matt, I like you're thinking on the low increase for the insurance company!
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Post by: roger on July 27, 2006, 15:11
So take it to its logical conclusion, if an insurance Company wants a BHP figure or increase, take 138 as stock - get it done on a hot day, and as you say Matt PROOF - only 1 BHP.

Me thinks they might smell a rat, or come to that if its a Direct Elephant type company they are probably too thick to recognise it.   s:wink: :wink: s:wink:
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Post by: Anonymous on July 27, 2006, 17:43
It IS quicker   s:D :D s:D   WOOHOO   s8) 8) s8)  

Just done a few of the familiar routes. Managed a sub 7s 0-60 as well with a bit of a boggy start (GTech)   s:) :) s:)  

On the private road that I use a lot (cough cough) I managed to get to 115mph instead of the usual 105mph at the end of the dual carriageway.
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Post by: Anonymous on July 27, 2006, 20:00
I have no idea what the figures are for mine with the chip but like they say the butt dyno is best. I find it a lot more flexible at the lower end than it used to be and like you there is a 'private' road that I always use and pre chip was a max of 105-110' after this was around 115-120, having said that when I tried the 190 Celica on the same private road it hit 125 easily  s:( :( s:(
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Post by: Anonymous on July 27, 2006, 20:55
Quote from: "Les"having said that when I tried the 190 Celica on the same private road it hit 125 easily  s:( :( s:(

Well yeah, buts its a 190bhp as standard !
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Post by: kanujunkie on July 27, 2006, 22:12
do remember that an engine ages as well, i remember the old supercar issue of top gear when they got just over 110Bhp out of a Dino  s:lol: :lol: s:lol:  

IIRC

plus of course air temp is a great sapper of those horses
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Post by: roger on July 30, 2006, 17:15
Some claims really do take the p*ss though...

(http://gallery.maxima.org/d/9253-2/350zdyno.jpg)