mastermayhm

Thanks!

Case1906

They are not same, unless you mean they result to similar performance numbers. The volume tuners get there in different ways and the power bands will be different.

Skilly

True, but I would go further than that after digging in deeper.

There are some tuners, like OE (pointed out earlier) that appear to use one map for all 4 versions of the GT - which of course will produce the same results across each and they claim 617hp (surely measured at the crank)..Im sure its easier; they only have to maintain one set of software across all of the options.

With others (the 2 I could identify were Weistec and RENNtech) there ended up being two different maps. One for the GT/GTS and one for the GTC/GTR - the differences in each tune result isn't trivial. It gives the GTC/GTR a reward for their different config of (at the wheels) 51hp/ 29lb-ft. And it seems to go across the profile rather than just a peak.

Bottom line though, you are completely correct - they are not all the same.

Hetzle

Given your comment on "volume tuners" it sounds like you might know of some specialized ones, who could develop bespoke tunes for more highly modified cars. I am curious - mind sharing?

Skilly

I see youre in the Bay Area - if you are looking for someone who's well known in these parts and provides a more personal approach to tuning, you may want to reach out to Shiv @ Openflash Performance. He was recently featured in Car and Driver for tweaking the HP/lb-ft on a Lambo Urus. I know the owner of the car - its FAST(er)!:

https://www.openflashtablet.com/blog...borghini-urus/

He's located in the East Bay.

Case1906

There are a handful of independents out there who do tunes tailored to your specific car. Many people don't appreciate the fact that every car is different. If you put two "identical" stock GTs on the same dyno on the same day they will turn (sometimes alarmingly) different results. The tuners we are discussing are very good, but generic from this standpoint. In the DMV there is a relatively new shop call AMG Tai's which is set up to do custom tuning.

kumizi

You guys must all be attorneys and have never tuned a car before. Paralysis by overanalysis.

If you speak to the tuner at OE tuning, Eurocharged, or even the guy down the street that tunes Mustangs, they will tune your car based on what it is and it will perform the same as a Renntech tune.

You keep going off website information. The guy answering the phones or updating the website at a "volume tuner" probably doesn't know or give a **** about the differences considering he might sell 1 GTC or GTR tune every six months. It's not a matter of capability or the tunes being different.

I perfectly understand the comfort factor in going with Renntech. They a have a great reputation. They've laid out all the information for the consumer. But tuning a stock car is not brain science. If you were to try and explain to a room full of engine tuners how your Renntech tune is "different," they would probably bust out laughing.

edit: In a way, you guys are right. If you just want to hit checkout on a website and it show up two days later, Renntech is the most trouble free way of getting it done. You dont have to worry about reaching the right person to make sure you're getting what you need.

kumizi

I agree dyno tuning is best, although on a bone stock car I doubt there is enough variance to make a difference. If you live in a big city, go take a drive down to your local shop and talk to the actual guy that tunes for them. If you pay him for a tune, he will tell you the exact air fuel, timing, etc on your car and can even play around with other things like throttle response. It will help educate you and also down the road if you make any mods, he'll be able to retune.

BTW, I sent you a PM if you still want to sell that steering wheel.

Skilly

You said, the GT no matter the type is tuned the same. You are 100% wrong - web site information for the most part is what created this mess. It's all pretty shady and miss states a lot of specs (ie Weistec shows 148/181 across all choices with an asterix). None of the tuners specifically call out a different version of the GT tune for GTC/GTR, so in effect, if I were to want off the shelf and go by website feedback only, I would only have agreed with you.

I managed to gain access to engineers in both cases where I leaned in hence learning about the 2 different maps which you said wasn't available. Not 'bespoke' different from car to car...SMH.

The original question was centered on do they tune the same across all 4 car variants. Your'e choosing to either overlook or not believe that fundamentally the GT/GTS and the GTC/GTR are tuned with a different map, at least from RENNtech and Weistec (maybe more but I didn't verify). You came over the top early on being the truth police and now you seem to be doing what you said you wanted to prevent - misinformation.

gshoe777

Ok. OP is back with the stock dyno from today.

See the picture attached.

Little ticked off at the dyno place because they failed to mention that they didn't have the right connector to also read TQ. So we only have HP recorded today.

I had them run a session at Sport+ and also Race. You'll see the difference in the photo.

Race max HP to the wheels was 551HP
Sport+ max HP to the wheels was 506HP.

They claim the drivetrain steels 20% from the crank numbers but the Renntech and Weistech sites claimed that figure is 12% (to my memory)

Crank Calc for Race = 617HP-661HP
Crank Calc for Sport+ = 566HP-607HP

The car has less than 1400 miles on it. 93 octane. The temp in NY today was 73 and humid.

2019 GTC Stock Dyno.pdf

I'm going back to get the TQ recorded too before I add the tune. I'll upload that one as well.

Skilly

You're right on the 12% - they quoted that for me too (Weistec quoted 15%).

chris135b

Awesome numbers gshoe777! This is good to see.

-Chris

Skilly

I was thinking the same thing...had to look twice - pretty incredible stock baseline!

kumizi

Thanks for posting the dyno.

1. I am shocked at the difference between Sport+ and Race. Learned something new today if they really hold the car back that much in sport+ mode from the factory.

2. Each dyno is different but still those are surprisingly good results. Did they use a dynojet dyno? Will be interesting to see the after number.

DriveAMG

These are some awesome numbers! Can’t wait to see the torque numbers. I also am in disbelief on the hp spread between S+ and R...

gshoe777

Yeah I was totally bummed about the spread too. I hardly ever drive in race.

Forgot to mention. Yes it was a dyno jet. Or at least they said it was a dyno jet. I never saw it with my own 2 eyes.

Case1906

Kumizi-- Done deal on the steering wheel and I resemble the attorney remark.

Hetzle

Thanks for the suggestion but if I remember right Shiv has the reputation of making a significantly inferior product to the JB4 in the BMW scene and poor customer service... lots of drama around that guy.

Skilly

Any chance that you have the tune stats - really curious to see what it pulls out of the GTC. Also, to confirm, you went with the RENNtech tune?

gshoe777

parts just came in. Waiting to schedule second stock dyno so I can get the tq numbers.

I'll probably get both done at the same time. Stay tuned! No pun intended

chris135b

Very cool! It will be interesting to see your numbers with the tune! Renntech has on their website says 580 hp/540 tq.

Take care.
-Chris

G. P

Hi gshoe777, just one correction:

@ 551 WHP with GTc Drive train loss of 12% your crank HP is actually : 551/0.88 = 626 HP. At 20% loss 551/0.8= 688 HP. This is because you measure a loss so the approximate calculations method is WHP/(1-loss%)= HP@crank
( 626 HP - 12% gives you 551 whp).

Regardless, these numbers seems to be at very high delta from stock. The graph looks like a DynoJet plot, which always run higher then Mustang and others (some estimate it at 9-12% higher).
Next dyno pull , ask to print the Test Condition data. It will be interesting if they use Correction Factor of 1.0 or higher. That could explain the higher numbers.

Setting the HP aside, what really matters ( since you cannot change the stock values) is to see the gain between Stock and Tune.

Good luck with the pulls and let us know when you have the results.

Skilly

since the stock baseline readout is so much more performant than stock (in his readings), I'm going to be more interested in the delta for sure.

G. P

Agree, the most important is the gain we get.

gshoe777

Random question.

I also have some bmc air filters. Should I install them with the tune before the dyno or do you guys want to see just the stock car plus the tune?

I'm considering installing the filters last and doing a third dyno to see if those bring any gains. I dont know if that's worth doing though.

Thoughts?