ISF 2008 - BHP

[AB1]

Hi ISF owners,

I was wondering if anyone with a 7-9 year old ISF has recently had a rolling road BHP test? 

If yes what was your BHP?

Was that taken from the crank/flywheel or the wheel/tire?

Ive just had a new short block replaced along with a complete clean and rebuild (paid for by Lexus under my extended warranty 12k cost!!) after my engine was losing loads of oil but upon having a BHP test I am only getting 365 at the crank which is nearly 55 BHP down on what it should be. However Lexus are telling me that is about right for a 8 year old ISF so Im looking to see what others are getting from a 7-9 year old ISF (standard build - i.e. no enhancements)?

Thanks

Aaron

[Martin F]

Was this measured on an engine dyno or a chassis dyno?

The only true way to measure engine BHP is on an engine dyno, anything else is an estimate, and those estimates are a lot less accurate when the car has an autobox like the IS-F. 

[mrfunex]

That’s not right. Something hasn’t been put back together correctly - modern engines won’t lose almost 15% power in 8 years unless they’re mega, mega high mileage, or broken. 

 

Or, as MartinF says, the measurement hasn’t been done correctly. What type of dyno did you use?

[AB1]

Ive done 100k miles from new.

All I know the test was done at the crank.....as a guide an RCF was also tested on the same day also at the crank and it produced 460 BHP, ok this was only 1 year old so i would expect it to be close to its original claim, but the point is its the same same test and huge difference. 

I actually used Surrey Rolling Roads in Farnborough (who was recommended to me by a Lexus mechanic).

So have you guys had a BHP test?

[Jgtcracer]

May be worth getting a second dyno run somewhere else to see how the numbers compare.  There's no way it should have 365 bhp at the crank.  Even at the wheels it seems a tad low.

It's also interesting that you had this work done, haven't heard of such a big warranty claim on an ISF in the UK.

 

[Flytvr]

Does it feel down on power?

ive been in a few trips alongside other Fs and they all seem to perform the same.

[stevet]

Never known an ISF engine to be replaced yet. Did they say what was the cause of the oil consumption?

[Mark G]

Two things here, the BHP figure is way too low and what went wrong with the engine, they have replaced the block, presumably due to bore wear, what about pistons, are they the originals because if it was losing that much oil that it needed a replacement block I would have thought other components would have been replaced also.

As others have said, does it feel underpowered?

[Warrington guy]

did they take it from wheel or fly/wheel365 bhp is pretty much bang on at wheel

[AB1]

they took it from the crank (which I believe is the same as the fly wheel), but as an RCF was tested also at the crank with 460 BHP i have to believe something is wrong

[Big Rat]

According to The Rat data bank NO engine has lunched itself that was running normal spec AND had been maintained, oil level and so on.

There have been 4 engine strip and rebuilds 3 in the states and 1 in Canada ALL as a result of massive overload of Nitrous........ 🙄

Only one transmission replaced due to massive implosion when it received a software update just prior to delivery to customer in Australia.

🐀

 

[Big Rat]

6 minutes ago, Big Rat said:

According to The Rat data bank NO engine has lunched itself that was running normal spec AND had been maintained, oil level and so on.

There have been 4 engine strip and rebuilds 3 in the states and 1 in Canada ALL as a result of massive overload of Nitrous........ 🙄

Only one transmission replaced due to massive implosion when it received a software update just prior to delivery to customer in Australia.

🐀

 

Big Rat

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Posted February 26

First recorded instance of major transmission software malfunction in Aus, not happened since the gearbox was replaced, by Lexus under warranty amount not disclosed 😳

[Warrington guy]

AB1. If it’s from fly/wheel there is something serious. You need to get it checked out. 

[Martin F]

1 hour ago, AB1 said:

they took it from the crank (which I believe is the same as the fly wheel), but as an RCF was tested also at the crank with 460 BHP i have to believe something is wrong

Nope, Surrey Rolling Road only have a chassis dyno so the power will have been measured at the wheels and the crank power estimated. 

As I mentioned before, measuring this way you only end up with an estimated crank figure as the only way to obtain a true crank power figure is to remove the engine and place on an engine dyno. However it is interesting that an RCF was dyno'd the same day and they reported a significantly higher crank power figure, however you don't know if they were using the same or different algorithms to estimate crank BHP. Do you know what the wheel HP figures were for both cars ?

 

 

[Neil E]

As David and Martin said, it's only going to be an estimate based on the power measured at the wheels.

Does the printed dyno sheet list the settings used and the conversion from wheel HP to flywheel HP? 

As a very, very rough calculation allow 15% for auto transmission loss and the measured 365 whp = approx 420 flywheel hp. 

Here's a print showing a stock ISF at 357whp on a Dynojet machine which I would think is similar to Surrey RR.

 

 

[AB1]

thanks for al the comments guys...much appreciate. 

Lots of mixed messages so still confused. 

Im not a mechanic so you'll have to bear with me but Charlie at Surrey RR said the measurement was taken at the crank, plus the RCF which performed the same test after me was pushing 460BHP so theres a huge difference even if the car is only a year old.

 

[mrfunex]

The RCF is supposed to have 467bhp (or PS?). 460bhp isn’t a ‘huge’ difference at all, and works out to be 466PS. 

Either the wrong correcting factors have been entered for your ISF, or something isn’t working right. I’d get it looked at. 

[Bluethunder]

1 hour ago, AB1 said:

thanks for al the comments guys...much appreciate. 

Lots of mixed messages so still confused. 

Im not a mechanic so you'll have to bear with me but Charlie at Surrey RR said the measurement was taken at the crank, plus the RCF which performed the same test after me was pushing 460BHP so theres a huge difference even if the car is only a year old.

 

How does the car drive/perform?  

[Neil E]

The measurement is taken at the wheels on the rollers and from that whp reading the Dynojet software can estimate what the power at the flywheel is. The tester does need to set the machine up correctly to get a reasonably accurate estimate.

Surrey RR do have a very good reputation, why not give them a call to confirm and clarify the result? I think they will say it is 365 hp at the wheels. If they still say 365 was measured at the crank, ask how it was tested.

This may help explain.

 

If you need a second opinion, I used Eurospec in Guildford the last time I tested the SC430 and they were very good. 

www.euro-spec2000.co.uk/

 

[Peter P18]

13 minutes ago, Neil E said:

The measurement is taken at the wheels on the rollers and from that whp reading the Dynojet software can estimate what the power at the flywheel is. The tester does need to set the machine up correctly to get a reasonably accurate estimate.

Surrey RR do have a very good reputation, why not give them a call to confirm and clarify the result? I think they will say it is 365 hp at the wheels. If they still say 365 was measured at the crank, ask how it was tested.

This may help explain.

 

If you need a second opinion, I used Eurospec in Guildford the last time I tested the SC430 and they were very good. 

www.euro-spec2000.co.uk/

 

Also used them. If it’s any help, we did a dyno day with TDi originally, and my results were awful! 

The auto was their reasoning for the poor results, but as others have said, you can make adjustments to factor that in so the results are more accurate. 

It’s not an exact science, but done right, it’s usually fairly accurate. 

That said, no two dyno’s are the same.

I’d get a second opinion from these guys. They’ve done a few ISF’s now, so you know they will get it right. 

[Martin F]

To eliminate all the estimation when comparing two cars on the same dyno it's better to take the actual wheel BHP. 

[Butchs13]

Dont think this has been covered here so.......

Did you have the Air Con on? the other car might not have it on.

Very interesting video where shows that under full throttle AC does not disengage compressor. I turn my AC off if the need for full power arises.

 

Cheers

 

 

[Flytvr]

1 hour ago, Butchs13 said:

Dont think this has been covered here so.......

Did you have the Air Con on? the other car might not have it on.

Very interesting video where shows that under full throttle AC does not disengage compressor. I turn my AC off if the need for full power arises.

 

Cheers

 

 

Totally agree.

Just listen to your exhaust note when you turn the AC off

[Warrington guy]

Flytvr that’s because you’ve a noisy exhaust fitted . 

[Big Rat]

@Warrington guy Dave I heard through the grapevine that @Flytvr was at the service reception of Cheltenham Lexus pleading on bended   knees  for them to fit @Mark G old system 😂

🐀