Finding My Lost Horses

[giblet]

Got the car on the rollers today, was too busy drooling over the other metal to pay much attention to my graphs. Only took a proper look at them once I got home.

These are the results -

67857

67858

67859

Gratuitous shot of the car on the rollers -

67860

My car is 100% stock, recently hit 50,000 miles and had an oil service a few months ago. Any suggestions on where I should start on my quest to find the missing horses? Current plan is to get the plugs changed, fuel filter is also due a change too. Not sure where to go from there, boost leak test?

[Nick Mann]

It's interesting that using your wheel figures and then adding the 24% loss from the drivetrain and 7% loss through the torque converter gives 1 hp less than your flywheel figure.

Your boost may be slightly low, but not much. Your afr seems to take a while to come down, although it certainly ends up over rich as per stock VR4s. If you had a significant boost leak I'd expect lower AFRs in the mid rev range.

Plugs and fuel filter will never hurt. What about the air filter?

[giblet]

Ah so the flywheel figure it seemingly spot on. Good point. I have a pipercross panel filter which I'll fit tomorrow. Not sure where to go from there. Worth upping the boost next week after having the intercooler and downpipes fitted?

[swinks]

Bit low manifold pressure for facelift vr4. Also, power curve rises up a bit late. I would check for boost leak.
Also, injectors may need a bit clean, running out of puff at high load.
Other than that, quite nice graph for unmodified vehicle.

[Davezj]

gib you are forgetting that your car is a auto and the flywheel figure has to divided by 0.93 to include the auto box fudge factor.

so you flywheel figue will be more like 263bhp which is a bit more like it.

but the 245bhp fly wheel figure is the 4th gear pull and the 3rd gear pull was 235 bhp wasn't it. which would make the ture fly wheel figure about 252 bhp.
but all you have had done is a fluid change, boost leak test, check plugs and possible change, change air filter, fuel filter, boost gauge to check that while the car is in motion.

[swinks]

Dave, all you need to remember is to read posts done by other users bit earlier. Re: your calculations read Nick post ;) Stop messing with Gibs mind please!

[giblet]

Thanks for all the replies. I had forgotten the correct algorithm for calculating flywheel HP based on wheel HP.

Looking at the history paperwork the plugs are well overdue a change. I'll move up the 7's since I'm planning to get it remapped at some point. I think the fuel filter is also long overdue a change. Discovered an issue a couple of times now when my fuel light has been on. Under WOT the car just gets to 80 and seems to die. Engine stutters and the speed and revs drop. It has only happened twice but has scared the life out of me each time, as a result I've been taking it easy as soon as the fuel light comes on and just coasting to the nearest Shell. Might be easier for me to get a second hand set of injectors and have them cleaned before fitting them.

[Davezj]

Dave, all you need to remember is to read posts done by other users bit earlier. Re: your calculations read Nick post ;) Stop messing with Gibs mind please!

you are not reading my post tomasz,
the 246 was a 4th gear run not a 3rd gear run, the 3rd gear run produced about 10bhp less than the 4th gear run. so if you take the normal 3rd gear run of 235bhp and do the auto box correction it gives you 252 bhp.

4th gear runs give you a bigger power output i don't know why it just does. this was proven on the day. the dyno operater said he always used 4th gear for the dyno days as this gave a gibber bhp out and everybody love more bhp. this kind of proves why the Aus and NZ dyno results always seem to be higher, they do the dyno runs in 4th normaly.
giblet did not explain this 3rd gear, 4th gear discrepancy properly.
the auto box correction still has to be done on the 246bhp run but it is a high output 4th gear run.

[Davezj]

It's interesting that using your wheel figures and then adding the 24% loss from the drivetrain and 7% loss through the torque converter gives 1 hp less than your flywheel figure.

Your boost may be slightly low, but not much. Your afr seems to take a while to come down, although it certainly ends up over rich as per stock VR4s. If you had a significant boost leak I'd expect lower AFRs in the mid rev range.

Plugs and fuel filter will never hurt. What about the air filter?

there was no auto box correction done on the day to my knowledge.

my result was 222 ATW 285 ATF

222 with 24% added is 292 and 7% added to that is 314 so deffinitely no auto box correct added on the day.

gibs result is add because it 4th gear run not a 3rd gear run like normal.

[Nick Mann]

So you lost less horses than Gib? That would suggest that Gib is losing a much bigger percentage in his drive train?
My point was that 173 to 246 is almost exactly the standard loss percentage that we apply to an auto vr4.

[swinks]

Seconded to Nick.
Sorry Dave but now you are doing simply witchcraft.
If you find a little bit time, dig out our previous RR Days results figures WHP vs. FHP. Gibs printed calculation of wheelpower and flypower is almost spot on.

[giblet]

Sorry I forgot to mention the gearing issue. I was too busy looking at other cars to pay attention when my car was being tested. The operator did a couple of runs in 3rd gear and a couple in 4th. The numbers were higher in 4th and the printouts above are from the 4th gear runs. I believe Daves figures were from 3rd gear runs as his previous dyno runs have been done in 3rd gear so it made sense to stick to that for comparable figures.

[Davezj]

wichcraft now that is the Aus and NZ dyno figures.
my response to that is yes whichcraft they use 4th gear to do the run's in.

what you have to do is forget the 246bhp figure and work on a 235 bhp figure, unfortunately i do not know what the ATW figures were for the 3rd gear run was but it can be roughly worked out by back calculating.
what you are forgetting is what we now know to be true as of last saturday. if you do a power run in a vr4 in 3rd gear you get less BHP than if you do a power run in 4th gear, so the club basic factors for drive train loss is not 24% in 4th gear for some reason it changes. i don't know why, it could just be the dyno operator fudging it, but it does change.
it can be seen from gibs result. i say again in forth gear gibs car made 246bhp at the fly from 173bhp at the wheels. There was no auto correction done on the day for the auto box cars.

my run was in 3rd gear. the dyno operator said that you get more bhp from the car in 4th gear than you do in 3rd gear. and according to him that was just a fact.

so you are going to have to just believe me when i tell you this. i know it is hard to believe but it is supposed to be true.
the 3rd gear run ATW figure must have been lower than that achived in 4th gear and the transmission losses in 4th gear must be different than in 3rd gear run. i believe the dyno has to be reset to change the gear ratio when changing the gear the dyno does the run in, i am not saying this was not done, i just don't know. what i do know is 3rd gear is a 1.3ish ratio and 4th gear is a 1.0 ish gear ration. you can draw your own conclutions from that.

normally on the print out there is a little box of settings that say what the gear ratio is set to. if you look at my dyno result the setting says my gear is 4th for the run which is true for the petrol run, which was the last run he did on my car, he did not do what i asked for and that was a 3rd gear run. but my LPG run was done in 3rd. which is why my petrol was about the say power figure as the LPG it should have been about 15 - 20 bhp less than the LPG figure.
i know this because i was logging the dyro runson my car. so i can see what speed the car was doing on each run.

so really the figure form this day are not that comparible with anything that has gone before if he used 4th gear to do the run. which i suspect he did.

but i can only repeat that there was no auto box correction done on the day.
you just have to look at my result 222 atw 285 atf 307 after auto box correction.
if i used the 245 and 7% my result would have been 222 atw 292 atf and 314 after auto box correction which is about right form other dyno results i have had. the actual dyno atf figure is slightly less than the 24% we tend to use a basic calculation.

[Ryan]

*yawn* This corker again.

Not sure where you got your info from but the dyno runs I've attended have been in 3rd gear.

[CANDEE]

It shouldnt matter which gear its done in as long as the final drive ratio has been set correctly by the operator...

[Davezj]

i have seen plenty of result sheet that say they are do in 4th gear, i trawled the site and looked at most of the posted dyno results and asked the questions i could. now i am not saying all of them are 4th gear runs but a large proportion of them. this is something i have looked at in the past, but i did not believe it would make much of a difference but after the run on saturday i an convinced.
this is why i want to do a proper test on my car with some one to one dyno time to the runs i want to do so i can have my own data on this subject.

[Davezj]

It shouldnt matter which gear its done in as long as the final drive ratio has been set correctly by the operator...

this is what i understood to be the case.
but some dyno operates get better results than others there are always ways to fool the punter into thinking they have got a better result than they actully have.
but if i can do back to back tests on the same dyno on the same day i will have my own data to look at and i can draw my own conclusions.

[CANDEE]

this is what i understood to be the case.
but some dyno operates get better results than others there are always ways to fool the punter into thinking they have got a better result than they actully have.
but if i can do back to back tests on the same dyno on the same day i will have my own data to look at and i can draw my own conclusions.
Thats why its a case of going back to the same dyno everytime, with the same operator. Then you get comparable results as they dyno's should take into account the different day/conditions into the reading. At lease this is the case with a Dynapak.

[Davezj]

yes i am hoping to go to a more local dyno operator and and try a build up a bit of a relationship with them and do all my dyno work at there facility. all the dyno runs i have done so far have always been on dyno days so they have always been a long way from my location to make easy for more members to get there, i have ended up driving 100miles or more just get there.
apart from the last one which was only 50 ish miles away. so till not conveniant.