Differing dyno results
 

Hi guys, was just after some opinions of peoples past experiences when using two different dynos.

Brief spec is

Forged EJ207 2.1 stroker
1050cc injectors
GT3071r
WR1 AVCS heads
Spec C inlet
Syvecs ECU with flex fuel


When my car was originally tuned (before I bought it) it made over 500hp with 20% methanol mix and a tad over 480hp with just pump 99ron.

Not long after I bought it, I had a map sensor go down, so took it to a mapper in my area to sort it out and give the car a once over for peace of mind. They told me the existing map was spot on, however the initial power figure may be slightly optimistic. When it was dynod this time, it only made 394hp albeit on a completely different roller…since I’ve owned the car it definitely doesn’t feel like it’s lost any power, let alone nearly 100hp. The tuner also mentioned the GT3071r I am running, is likely at its limitation within the 380-420hp region when looking at the compressor graphs for the turbo.

Has anyone else seen such a great difference in results between different dynos? Obviously there’s lots of variables to consider when comparing the two, I just wondered if anyone else has had any similar experiences.

Thanks in advance.

There's a number of possibilities here.
Engines do lose power over time. I have mine dyno tested annually and see a slight drop every year.
You say the original power figures were taken before you bought the car. Now car sellers never exaggerate do they?
I have seen engines set up by 2 different mappers. In each case they dropped power within a month. I mentioned this to the dyno operator. Apparently it's not uncommon for mappers to map an engine for max power for the customer to see then turn it down a bit for safety after the last dyno run.
Having said all that, 100bhp is a lot to lose and would be very obvious. I suspect those horses weren't all there when you bought the car.

Yes I agree it’s not uncommon for engines to lose power, however as you and I say over 100hp is an awful lot to lose. I’m also well aware that cars on the dyno will likely produce safer power on the RR than in real road conditions if the fuel system for instance isn’t up to the job, after all the car isn’t sloshing fuel around everywhere when on the road so I could see why a car may be down tuned for these circumstances. What doesn’t add up though is It was mapped in the early august and I acquired the car approximately 6 weeks later. Without there being a serious mechanical issue which was then amended and subsequently downtuned for safety, I can’t tell if one or either of these figures I have on the printouts being totally accurate. When looking at the GT30 compressor graph, at approximately 2.6 on the pressure ratio scale, the turbo is in the 74% efficiency band which across the scale equates to around 40lbs/min on the air flow scale, roughly 400hp. This 394hp figure is for the high boost 1.7 bar map. The low boost figure despite only being 1.3 bar still achieves 382hp. This is where I start to question the turbos ability. I will add despite the figures, I’m terms of drivability the car is fantastic and is seriously quick compared to some modern “fast” cars, the map on it has been spot on. I suppose my main question is, can a GT30 in standard frame realistically make the quoted power and if not what’s the best upgrade?

the results from one rolling road to another can differ greatly , sometimes tuners will estimate power due to no rolling road , were you told engine or wheel bhp , the v8 club i’m in use Surrey rolling road as they are well known for being more accurate , others have come from other rolling roads and been disappointed 😁 , the person doing the rolling road being ambitious as above converting wheel bhp to engine bhp , the owner adding a bit more etc 😂😂a good example on the monaro , gearing is very long , change the rear diff they say it’s worth 50 bhp , i did change the diff , but can i really say it’s got 50 more bhp or just explain the diff change is equal to an extra 50 bhp , they do a 4 k £ tuning pack they say it adds 100 bhp on a na engine , it probably does but by the time you work out wheel bhp it would be around 75 bhp , as long as the engine is good , and it’s running well and has a clean bill of health then you have some good power there 👍

All the above figures I’ve mentioned are corrected flywheel. My car was originally tuned at Surrey Rolling Road when it made the highest figure of 520hp.

Even a Gen 1 GT3071r should make 450bhp, with the Gen 2 making ever so slight more due to improved compressor wheel aerodynamics. I’d say that whoever told you the GT3071r is a 380-420bhp turbo is really underselling it capabilities. I have seen a number of 3071r’s do between 460-490 on pump fuel and as much as 530 with a meth mix.

Is this on a rotated set up or seen on standard frame set ups aswell? Mine is a fast line one with VF style housing, Garret core none rotated.

so best comparison was wheel when it was tuned to wheel now , could have been a cold day v weather now which is warming up , as above main thing is the car running ok in its current set up , going to the fly v wheel , on a rear wheel drive only it’s between 20 to 25 percentage loss from fly to wheel , this will increase per cent wise with more power so could be 30 per cent , this is worse on a four wheel drive , so there maybe nothing to worry about , on 500 bhp fly you are probably loosing at least 100 to 150 any way

That’s on a standard location setup. If you are using a Fastline unit you may have seen the black Hawkeye he uses in some of his advertising, that particular car was built by Enginetuner and produced 489 on 99 Ron and 530 on meth on a 3071r Gen 2.

Do you have the RR graphs? As already stated the gt30 is a 450+ bhp turbo.....is the car laggy?

Yes mine is a fast line unit, not sure on whether gen 1 or 2 though. It has quoted 520hp on meth and 480hp on 99. Mine was built at chevron and mapped by racedyanmix. I will reiterate it drives amazing, I just wondered why I have such varying graphs between two sets of rollers.

Its quite laggy yes, starts coming alive by about 3.5k then full boost I think around 4-4.5.

Printouts here, second one might be a bit awkward to read from the angle I took photo….
https://cimg9.ibsrv.net/gimg/www.sco...bcf6a0caa.jpeg
https://cimg0.ibsrv.net/gimg/www.sco...92e2046df.jpeg

They look completely different lol, get a third opinion if you can as I’m guessing a gt30 at 1.7bar will be more than 400bhp unless there’s something wrong.

400bhp is fast but a properly set up gt30 is another level....do you know the person who sold you the car or was it via eBay, Facebook etc...?

Yes they do look a bit off don’t they. It was a chap from Facebook, I’ve had it since September now and don’t get me wrong it’s a fast car but I’m not sure it’s at its full potential, obviously the power figures vary massively so I do wonder if something is wrong. Reason I had it dynod was because it had a running fault, turned out to be map sensor but with it being in syvecs and me not having a laptop I couldn’t read the data to diagnose it so took it there. It makes 382hp at 1.3 bar and 394hp at 1.7 on the most recent figures, 12hp gain for an extra 5-6psi boost doesn’t seem right lol

Just to add this is the wheel HP figure on the higher boost setting. They did mention the erratic operation of the boost solenoid for whatever reason on the higher setting…
https://cimg1.ibsrv.net/gimg/www.sco...0a15fe09c.jpeg

You might want to get the car remapped mate. I'll leave it at that for now.

Chevron motorsports were used by @The Joshua Tree and he had a lot of positive feedback about them. Drop him a line and I'm sure he will tell you to also get your car remapped.

Honestly mate I’ve got no complaints with any of it, runs and drives great, engine has been spot on. Not here to slag anyone off just wondering if I’ve got an underlying issue with car which has lost me +100hp or if some of the results are just under/over reading

Can you take a picture of the turbo?

id be paranoid after seeing the difference in power that the turbo had been swapped over before the sale as TEG MOTORSPORT have a good reputation

I was trying to be as political as possible lol. Sorry about that :)

You've had an engine built by Chevron, one of the best in the business so you're good on that front.

The mapping was based on something that @johno01 has just covered. These cars were worth more in bits. Sell some of the high ticket items and swap them for cheaper or lower spec. The ECU will try and compensate. Another thing might be your bezzy mate has a 'wicked map' that goes like 'brap'. Load this map on mate and you'll get an extra 200bhp - source trust me bro. Except it doesn't quite work like that so someone might have uploaded a new map and not backed up the original.

But a good reason to get a remap when you buy a car like this is because we all have different preferences and might want different features mapped in.

When Rob bought his the car was already mapped but he chose to remap it again and preferred it after because it was to his taste.

On my car the ECU allows multiple maps but I chose to have the one map with launch control and no anti lag. If I was to sell the car I can imagine someone would want multiple maps.

Alternatively the car wasn't mapped properly, not by the mapper mentioned etc, loads of reasons really.

yes they did a fantastic job of sorting the running fault, I noticed it says Blouch. Not sure if this is because can’t actually run a Garret housing in standard location though?
https://cimg7.ibsrv.net/gimg/www.sco...d3359aa98.jpeg

No worries at all, I just wanted to clear up I had no issues with any of the tuners haha! But yes some parts may have been swapped, but the vast majority of it I have checked over has been pretty much spot on. Maybe better off as others have said, 3rd dyno run for reference and go from there.

swerve the dyno for now mate, get a specialist to inspect the turbo and double check it is what you think it is...get it removed for an inspection and take it from there.....if the turbo is a genuine gt30 then your way down on power for some reason. On a positive note..if it is a gt30 and your happy with the power now then wait until it’s set up properly...mental....I went from 400bhp on my last blob to 480bhp thanks to scoobyclinic and it was a HUGE DIFFERENCE!!! 👍👍

I only recommend get the turbo inspected as I’ve already mentioned TEG MOTORSPORT have a good reputation and I’m sure they would have found any other issues which may have been holding back the power 👍👍

let us know how you get on 👍

spoken to fastline and they mentioned it’s hard to say without having it or seeing invoice, but they did mention Blouch is the GT30. A bit stumped with it really, had no problems showing a Lamborghini Urus a fresh set of mudflaps this evening though 😂