BGB Motorsports

If anyone is really curious about these runs and wants to examine them in the same way i have, here is a link to the software from the dyno manufacturer.
http://www.powercommander.com/downlo...6275.16855.exe If you email me at the address listed on our web site, i can send you the actual raw runs and walk you through how to view them.

There is no slight of hand going on, no one is "moving" anything and i am sorry that the owner did not run his car all the way to the rev limiter every time during his dyno run. I am pretty conservative in my estimates of these modifications and i was impressed with the results. In an effort to keep this thread constructive in a manner in which i would like, i ask that anyone with questions interested in these mods feel free to email me directly or call the shop; otherwise i want to wish you all a Feliz Cinco de Mayo. Have a good weekend!

thigos

This is the problem with RL. A member shares objective, although imperfect information, with the sole intention of sharing results with the community. I am not selling anything and have nothing to gain from posting. I just like this forum; I get a wealth of great information here from people sharing, discussing, and arguing over topics.

What I did was post the pic I took of the computer screen right after my post-tune dyno runs. I am glad that it was criticized and made us ask more questions. Helped clarify some things and I now understand the mathematical equation for torque. lol

The problem is, I feel for the vendor. All of us preach that we want transparency and objective data from vendors. Then when these types of posts go up, there are always a few people who want to discredit the results or process, which is fine. But to insinuate the the data is fake or has been fabricated is bs. No wonder most vendors play their cards close to the vest and don't give the community a peek behind the curtain.

Sorry John that you had to go into defense mode over this nonsense. I am going to continue to post the results of further tuning and my personal impressions of the product and experience. I know there are people who are getting some value out of it. But I am not going to respond or try and prove anything to members that are claiming that the information has been tampered with.

Thanks John for your commitment to these cars and to the people who love driving them.

kahane18

^^^^

What he said...

trebien

I agree... this is.

I don't think anyone insinuated that; I sure didn't... was just calling out what was clearly incorrect data. In my mind, I simply chalked it up to an improper measurement environment.

Yargk

Thanks for the info.

Warwick Morris

A very fair answer IMHO.

switchface

Thanks for sharing. Is the interpretation from this graph that the headers only really show their potential when paired with the TB+plenum+tune? Many have said headers-only wake up the car and it should have came from the factory this way, but with this chart at least its almost tough to tell which is which.

cox1974

The sport headers add something in the midrange...the whole package change the car behaviour completely in all the rpm range...

CAlexio

Funny after 93 pages and many of us who have transformed these engines and testified to the positive and noticeable change, how much skepticism there is still

BGB Motorsports

I know. I'm sitting on a dyno comparison that DeMan did Monday of the Stage III 4.0L X51 GT4 with full race exhaust vs a bone stock 991 GT3RS 4.0L; while I almost fell lot of my chair when I saw how great of a picture it paints, I'm hesitant to even post it given the fallout that will occur. It's Deman's build and his information and he wants to do another test and i can't release anything til he tells me.

RennOracle

The magic 470 at the wheels?

trebien

Somewhat. Another way to approach the data is that the GT4 has problems breathing up top due to the restrictive TB and plenum design, so these also need to be added for maximum flow at the upper end of the RPM ranges. On top of that, the tune helps the car breathe harder up top with the newfound airflow.

Essentially, the GT4 power output is hobbled in several different ways from the factory, and no single piece or part will create huge gains on its own without supporting infrastructure to combat limitations designed into the car in the other areas.

The GT4 has a lot of potential for added power, but needs several pieces working in unison to maximize that potential.

legin

I see an alternative order which is Tune, TB then header. I have tried Tune and TB and would say the tune also delivers on the low end torque dip that the headers apparently do it makes it more responsive low down compared to OEM tune.
This is the Ehresmann upgrade path build up as it happens. The ease of tune install and removal makes it the best bang for buck, when i fitted TB it was better for sure but not so much and a pain to remove and refit for warranty work. Currently i have just the tune and undecided whether to bother with TB refit. I cant comment on the headers as I havent tried them. Anyone done the headers as the final mod that can comment ?

John@Fabspeed

Couldn't agree more with that statement

John I would LOVE to see that dyno data! Email, phone call, text, teleport whatever is fastest and most convenient for you

I agree with this majority of this as everything on the car comes together for a cumulative gain that is very impressive for just basic bolt-on performance deltas at up to about 50whp/65wtq. Now of that potential performance delta I would say (and i'm sure many other shops and those with the products installed can attest to this) a solid 75% of that performance potential in located in the headers and the software. That additional 25% or so is a good amount of power to have, but it has less of a return on investment compared to the headers/software as it is made up of basically the catback exhaust and IPD Plenum/TB package. This is all given you have the factory 3.8L and not a crazy built motor by John or Rick, at that point restriction potential of different products undoubtedly change.

Haven't really heard of anyone pursuing it that way before as it is a little unorthodox. Would love to set you up with some headers as i'm quite confident they will exceed your expectations of performance improvements. Would also be a rare occasion to get feedback on the improvement from someone starting on the opposite end of the spectrum.

switchface

Not sure if this (or either of the John's) comments are necessarily directed at me, but I'm not skeptical of our tuner's contributions, just trying to better understand the dyno plots and educate myself.

I had some Fabspeed bits and race headers installed on my 987.1 CS. I was extremely happy with their customer service and communication, but I added those mods, not in search of power, but because the car sounded pretty tame in stock form. I got just the amount of aggression I was seeking and was very happy.

For my GT4, I like the sound it has now and don't want to change the pitch or tone too much. I can see how the full package makes a difference, but that brings up warranty concerns for me. Everyone has said headers-only is a great addition, I don't doubt it, but I imagine much of that is feel/sound. Not that there is anything wrong with that, but I'm not necessarily seeking that. I would be interested in more power, but am weighing that against unwanted sound changes and/or power delivery and warranty concerns, as this is my daily driver.

There are numerous threads, for a variety of mods, showing different dyno plots...but despite asking, I've yet to see a video of a pull between a stock and modified car to see how those mods translate into performance. Sharkwerks' original Kermit video did a great job of this, by showing a stock GT3 vs. their 3.9 Kermit so you can visualize the measurable difference their car pulled on the stock one. I'd love to see something like this - wouldn't everyone?

This isn't calling out anyone, or saying I'm skeptical, I'm simply trying to weigh my own internal cost/benefit analysis.