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Discussion Starter · #1 ·
My Elise has got a BWR s/c and the dyno said it is putting out 181 hp and 118 ft lbs. What happened to supposedly 225 hp for a BWR s/c? I know Dynos differ, but that much? The Dyno was done on a fairly new Mustang Dynamometer (the only one anywhere close). Has anybody else with a s/c had low dynos like this? Now I am beginning to wonder if I installed it correctly!
 

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that sounds very disappointing! I want to put my car on the dyno but I've been trying to find one here around Greensboro for a while now.
 

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There could be a vacuum leak, belt could be slipping, or your bypass valve could be stuck slightly open.

I would suggest hooking up a boost gauge.

Could also be the dyno, anyone else you know have results from this same dyno?
We had a dyno day some time ago here in Colorado where 4 BWR/Katana set-ups all put out 204-206whp, and my (at the time) NA elise put out 150ish.

So dyno's certainly differ.
 

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Mustang dyno's read high too -poke-
(sorry, come from the land of "real" dynos that are able to report to OEMs. Funny they might cost $4-6M and not read the high HP numbers that the $40K shop dynos put out)
Actually most "shop" dynos read high. It's in a shops best interest to report a high number. It's what their customers want/expect to see.

I thought the supercharger suppliers reported flywheel HP and not wheel HP?
I also always thought that is where our stock 190 HP # came from as well? So on the chassis dyno you would not see the 190# out of a stock car either.
 

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Yep. Stock is like 165-166hp at the wheels on my car. Reported crank is 190hp.
 

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How has the car felt since installing the BWR, what I'm saying is has your butt dyno felt different since install compared to stock.

i just finished installing my BWR yesterday and took her out for a 15 min casual drive and immediately felt the difference, there is a day and night difference.

Those numbers look like NA numbers?

Anyone else...
 

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Mustang dyno's read high too -poke-
(sorry, come from the land of "real" dynos that are able to report to OEMs. Funny they might cost $4-6M and not read the high HP numbers that the $40K shop dynos put out)
Actually most "shop" dynos read high. It's in a shops best interest to report a high number. It's what their customers want/expect to see.

I thought the supercharger suppliers reported flywheel HP and not wheel HP?
I also always thought that is where our stock 190 HP # came from as well? So on the chassis dyno you would not see the 190# out of a stock car either.
Generally agree with everything you put, all dyno's are however configured differently, and are at the mercy of whomever operates it.

The Katana/BWR ~220 horsepower number is the rating at the wheels, and has been verified by numerous dyno's, while some read lower, and some higher.

The stock Elise/2006 Exige whp numbers generally float close to ~160.
 

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rstutts, do you happen to have the dyno sheet on hand to upload?

It could be that the dyno operator didn't know the 8500 redline, or that your a/f mixture is rich.. or even lean, which could cause pinging and timing retardation.
 

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I thought the supercharger suppliers reported flywheel HP and not wheel HP?
...
The confusion probably stems from some dyno sheets that are posted here that are labeled "Flywheel HP". The term flywheel, in this case, refers to the dyno flywheel, not the engine flywheel. The result is really what is commonly referred to as WHP.
 

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Mustang Dyno's read VERy low compared to most other dyno. Dynojet dynos is what is most common in the USA and i think most people on this forum were using a Dynojet...
 

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I have the BWR with the PES reflash and took my car to the drag strip last year. I ran a 13.18 @ 105.74 mph in the 1/4 and I had a crappy 60 foot time of 2.031. Others on this board have ran 1.7 second 60' foot times. Compare my top speed to what Road and Track has for the Exige S 240; It ran a 13.0 @ 104.5. The slower top speed generally indicates less HP. I would guesstimate my HP to be around 250 at the crank. Take your car to the drag strip and see what times you turn. I'm sure there are plenty of strips around you;)
 

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I had before and after dyno readings done on a Dyno Dynamics dynamometer. In stock configuration, we got 155.4 HP and 112.7 FtLb torque. With the BWR installed, it was 189.7 HP and 128.8 FtLb. This was nowhere near the ~50 HP and ~25 FtLb torque increase that others were claiming, but the car seems to run strong. I had the tech who did the installation recheck belts, injectors, bypass valve, and do a smoke test to check for leaks. I think there are a lot of differences among dynos, but it's hard to conclude much unless you do a baseline pull to see what you are starting with.
 

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When someone in SoCal recently dyno'd his car on a Dynapak and a Mustang Dyno,
There was a 22 whp/25 torque difference between the mustang dyno and dynapack readings.

Works out to a 6.9% difference between them in whp and 8.5% in torque before any tuning was done

Yes every dyno is different, even 2 of the same dyno's will read differently.. and weather does make a big factor as well.
 

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Take your car to the drag strip and see what times you turn.
Trap speed is more indicative of a car's power-to-weight ratio. ET is much more traction/launch dependent.

Here's a quick summary of my drag events trap speeds along with their weigh-in and DynoJet SAE numbers:

  • 2005 Bone stock: 102.70 mph (167.31 whp @ 2100 lbs). 12.55 lb/hp.
  • 2006 Intake/Header/Exhaust: 105.06 mph (177.17 whp @ 2050 lbs). 11.57 lb/hp.
  • 2007 Katana Supercharger: 110.03 mph (230.87 whp @ 2070 lbs). 8.97 lb/hp.
  • 2008 Katana Supercharger: 112.10 mph (230.11 whp @ 2030 lbs). 8.82 lb/hp.
  • 2009 TVS Supercharger: (expecting 117-120 mph) I'll be bumping into redline @ 8500 rpm in 4th (286.44 whp @ 1980 lbs). 6.91 lb/hp.
 

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I am going to bet it is a bad PES tune. Call Charlie. Send your ECU and have it tuned right. I saw similar results on the PES tune and then found my long lost power by calling Charlie.
 

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I just had mine PES tuned, is there anyway to test to make sure the tune was performed correctly?

I'm hoping Fred will chime in on this thread

I am going to bet it is a bad PES tune. Call Charlie. Send your ECU and have it tuned right. I saw similar results on the PES tune and then found my long lost power by calling Charlie.
 

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Discussion Starter · #18 ·
Thanks for everyones help. I will try to put the dynos on here later tonight (when I get back). We did the first dyno in 4th gear, saw the results and tried the second in 3rd gear. The hp is almost a straight line at a 45% angle to 8300 RPM and the ft lbs is almost a flat straight line. I guess we should have went on to 8500, but it still would not have been a couple of hp more. On the second run, he also did an AFR (ratio).
 

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I dynoed my bwr with charlie tune and I have green air filter and larini se exhaust. I put down 235whp at ~8k. This was on a dyno jet. The question is, when you dynoed were there other people there dynoing before or after you? Were there results similarly low?
 
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