[Mk2] [Turbo] 500bhp on a 3071R!

[Jimbob]

I had a hose fail, after it came loose and rubbed on the ground, followed shortly after by a leak. Decided it was probably OTT anyway so got rid of it. Going to get an oil temp gauge so will soon find out I guess?

[3sgte]

Its on a home brew boot mount. 900x600x75mm by memory.

My full spec is in projects.

Cheers Marc, i'll pop over some time. How's yours now?

mine has been running spot on for the last year but sadly i think it has to go would like to have pushed more than 1.3 bar to see what it would do but just havent the time anymore

[Jimbob]

Pity, last time I went in it I was scared!

If you take any bits off before you sell let me come pick up those lights of yours!

[3sgte]

Pity, last time I went in it I was scared!

If you take any bits off before you sell let me come pick up those lights of yours!

no worries matey ,to be honest i recon it will be coming to bits to sell anyway

[Jimbob]

The sad truth mate is that thats normally the most lucrative way of doing it. My mate broke his Pulsar for £6.5k, he'd have been lucky to get £4k for it whole!

[RumbleStrips]

I'm really interested in one of these kits after seeing your results!

Any update on posting the dyno sheets?

[mikewright]

Excellent news jim. I know how painstaking a project this has been for you. One day when my one lives again I'll meet up with you and we can head out to a track.

[Jimbob]

Sure thing Mike.

I havce taklen a photo on my phone as camera is goosed, its okish but a bit shiney as I lamintaed them I'll post it up when I get 5 minutes.

[Jimbob]

Finally sorted a photo. Lost my phone lead and broke my camera!

Here is the power run, i'll take some piccys of the others.

[Kongaroo]

Nice power curve Jimbob

I hope you don't mind me asking but why was your Inlet air Temperature (IT) so much higher than the Ambient Temperature (AT)?

Normally there are only a few degrees between them but on yours there is a 29 degree difference?

Was the Inlet air sensor sitting in the exhaust stream?

The only reason I'm asking is I believe that if your 'IT' is higher then a Dyno Dynamics dyno will apply a higher positive correction factor to the power results.

[Martin F]

Nice power curve Jimbob

I hope you don't mind me asking but why was your Inlet air Temperature (IT) so much higher than the Ambient Temperature (AT)?

Normally there is only a few degrees between them but on yours there is a 29 degree difference?

Was the Inlet air sensor sitting in the exhaust stream?

The only reason I'm asking is I believe that if your 'IT' is high then a Dyno Dynamics dyno will apply a higher positive correction factor to the power results?

when i last got my car mapped the ambient temp was 27.1 with the inlet going up to 60 , mainly because the greddy fan wasn't up to the job plus the fan wasn't turned on, a couple of degrees difference and i would have been sitting with over 500 bhp myself now, darn hot days

have to say that is a very good map for a 3071 though, highest i have seen

[Kongaroo]

Are we talking about the same thing Marty?

The inlet air temperature (listed as IT on the bottom of the dyno sheet) is a sensor the dyno dynamics operator attaches to the car. I'm not referring to the MAT sensor in the intake manifold which is what I think you are talking about here?

[Jimbob]

The runs were all done using the IAT in my inlet pipe which sits before the TB. On the last few runs the temp was creeping up so we fitted an additional sensor in.

I am pretty sure the runs are uncorrected though. We just fitted the additional sensor to verify temps. The run previous did 498 before fitting it, and the temps dropped a bit for the final power run. Dave said we could sit around for half an hour and probably get even more once things cooled down, but I was happy enough.

[Jimbob]

The limiting factor for me was the temp getting up.

You can always fiddle here and there for an extra few HP, but is it worth it? Just get it driving nice and forget the numbers.

I am happy everything is really well matched on the car. I am going to get some better engine bay cooling, and get my pipes welded together to stop these hoses popping off!

[Kongaroo]

The runs were all done using the IAT in my inlet pipe which sits before the TB. On the last few runs the temp was creeping up so we fitted an additional sensor in.

I am pretty sure the runs are uncorrected though. We just fitted the additional sensor to verify temps. The run previous did 498 before fitting it, and the temps dropped a bit for the final power run. Dave said we could sit around for half an hour and probably get even more once things cooled down, but I was happy enough.

Hi mate, thanks for clarifying that. If the 'IT' sensor thermocouple was placed on your inlet pipe before the throttle body then that would explain the large difference between your ambient temperature and Inlet air Temperature.

But I think you are missing my point. There are very few ways in which the final power reading can be affected (ie. increased) by the dyno operator on a dyno dynamics dyno but the IT reading is one of them.

Usually the IT thermocouple reading will be placed in the inlet tract or airbox region of the car. This gives you a idea of what the air intake temperature is compared to the ambient. If you look at most DD graphs you will generally see IT is generally a few degrees higher than AT due to heat generated from the car.

By placing the IT thermocouple somewhere much hotter than ambient temperature a larger positive correction factor is applied by the dyno (automatically) so I am just querying why the IT was placed somewhere so much warmer than ambient temperature.

[Kongaroo]

PS: I hope you won't take offense by my query - I'm just interested in mapping and dyno results in general and I took my car to a dyno dynamics not that long ago to adjust my street mapped TD06 equipped car so I was just curious.

Well done and great build anyway

[Jimbob]

No offence taken, I got your point though.

The run previous to this had no thermocouple installed on my car. That run made 498bhp from memory. I am unsure where this correction factor comes from but its made 10bhp difference? Plus the car was actually cooler on the final run so would have been making more power anyway.

Dave and Mark where in charge of the dyno, I just watched an smiled.

Anyway, I can't get too excited about that. One becuase I don't know exactly how things are calulated, and two the car feels plenty fast enough.

[greeny]

Nice graph

How come the boost was falling off though jimbob?

[Jimbob]

Not entirely sure Michael. Mine is the 0.63ar exhaust. Dave said that the turbo was starting to run out of puff or hitting a restriction somewhere in the system.

I modified the inlet manifold but it could still be that as it is on short rev2 runners with a large plenum. But also all my boost piping is small and the intercooler is only 3" thick.

I tried to size things to keep spool best I could. I'm happy with what I made, but would like less lag. Dave did say a blue bottle would help that and I still haven't ruled it out, next year maybe.

For now I just want to enjoy it. I knew it would be hard work looking after it, but I have had an injector go booloo already. Keeps getting stuck open. Good news is got a new set on the way, so will have 3 good spares now!

I'm guessing next to go will be the clutch as its an RPS 450 and i'm making 467 at the fly.

[Kongaroo]

No offence taken, I got your point though.

The run previous to this had no thermocouple installed on my car. That run made 498bhp from memory. I am unsure where this correction factor comes from but its made 10bhp difference? Plus the car was actually cooler on the final run so would have been making more power anyway.

Dave and Mark where in charge of the dyno, I just watched an smiled.

Anyway, I can't get too excited about that. One becuase I don't know exactly how things are calulated, and two the car feels plenty fast enough.

I just want to clarify about the correction factor as it's fairly important and I want to let you know I'm not just being an ass and nit picking over what you assume may be only 10BHP

All dyno dynamics dynos run an atmospheric conditions correction factor automatically in shootout mode which is why they have inputs for things like Barometric pressure, Intake Temp, Ambient Temp and humidity. It is applied automatially based on these figures to try and account for the fact that a car will generally make less power on a hot and humid day compared to a cold one so that no matter what time of year you visit the dyno you will get roughly the same BHP reading.

Things like Barometric pressure and Humidity have relatively minimal effects on the final corrected figure but the Intake temperature is much more significant and is the one area that a dyno operator can accidentally (or on purpose) cause a genuinely inflated power figure on a dyno dynamics dyno.

This link is very useful and allows you to work out the correction factor that is applied when SAE J1349 is used:

http://wahiduddin.net/calc/calc_hp_abs.htm

SAE J1349 is popular and is the default atmospheric correction factor for many dynos although I cannot tell you for certain whether it is the default for dyno dynamics or not.

If you convert the relevant figures printed on your dyno sheet into the required numbers for the calculator (ie. kpa to InHg, Degrees C into F) and enter them it will tell you the correction factor that would be applied if SAE J1349 was used. Look at the difference between the correction factors between your recorded IT and if say the IT was only a couple of degrees above AT.

To save time it works out to be about:
0.996 for IT of 26 centigrade.
1.106 for IT of 53 centigrade.

Apply these to a car with 500BHP and you end up with final corrected figures of 498BHP for the car with lower IT and 553BHP for the car with higher IT. That is 55 BHP increase from having an unusually high IT value.

This is why Dyno dynamics in shootout mode always print those atmospheric conditions, ramp rate, shootout mode at the bottom of each graph so that it can be easily spotted when something like that has occurred. I've read that upto a maximum of 10 to 12 degrees C above ambient can still be considered believable but in many cases IT taken from the air intake box will often be only a few degrees above ambient.

Anyway like I said I admire your build and I'd be happy too if I got anywhere near your figures

For myself I'm actually going to try a downsize to a GT28RS so it looks like it's not going to happen for me, lol. SBITs is doing the work for me next week actually so I'm looking forward to seeing what all the fuss is about this low power 'spool monster'