Well, I held off on this mod as long as I could. At first, I wanted to make sure the maps were tweaked and no one installing would have any ECU/engine/trans issues from a reflash like this. Now that we are seeing GT-Rs running well over 500rwhp and not breaking stuff, I felt much better about adding the Cobb.

The goods...
I purchased the Cobb AP from Forged Performance in Marietta, GA. This shop has a great reputation and has supported our regional event, ZDayZ, for several years. In addition to purchasing the Cobb AP from them, I made the drive down Saturday to have the install done at their facility to ensure we could capture some same day before / after dynos.

Thank you's...
Before going further, thank you to Sharif and the guys at Forged Performance for taking great care with my car during my visit and walking me through the Cobb AP reflash process. This was the first GT-R they have had at Forged Performance, but I know it won't be the last. Also, special thanks to underpressure (Will) for some quick technical assistance regarding proper removal of undercarriage covers. We chatted with him by phone and, as I understand it, my stock dyno numbers are nearly exactly what he has seen for GT-Rs on this kind of dyno.

About the dyno...
Forged has a Dyno Dynamics 4-wheel dyno. It's a slick setup and allows a lot of corrections and ways to view the data. It is also known to pull lower lower numbers than similar dyno-jets when not using correction factors as we were yesterday. Regardless, we were not looking for through the roof numbers here. The goal was a safe install and to measure the actual gains.

Conditions...
Great day, low humidity, temps in the mid-30s. Last before dyno and first after dyno were separated by a time of approximately 75mins, most of which was taken up by downloading stock settings and uploading the 1.08 flash.

The Car...
My GT-R is pretty much stock with over 9000 miles on it. The only other mod I have are K&N drop-in filters, but I doubt they add much if any HP. Regardless, the baseline dyno and after were done with these installed already, so the relative change shown is all due to the Cobb tune. We installed the 1.08 tune for 93-octane gas.

Pics and details to follow...

PICTURES...

Apparently when you drive 4hrs for dyno runs and bring the first GT-R to visit the shop, you get a free car wash! Here, I step back and let Sharif get frostbite fingers cleaning the car while Sandy looks on. Wanted to make sure the redhead looked her best for the dyno and some publicity shots...
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There we go. All clean and ready for an upgrade!
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After putting the car on a lift to remove some of the undercarriage panels (to expose strapdown anchor points), the redhead is wheeled up onto the dyno and allowed to warm up for some baseline runs...
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After approximately 2hrs on the dyno (including warmup, baseline pulls, reflash, warm up again, and final pulls), the end results looked like this (more detailed commentary in following post)...
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You may want to consider changing the exhaust to something less restrictive. It seems that heat is something the std GTR already generates too much of, and taking some backpressure out should help drop the EGT's to a safer level - especially now since you will be elevating them with more boost and timing. That might also allow more significant gains to be achieved as well. The torque gains in the midrange look very nice.

So, lets talk about the gains...

first, for those looking at the absolute numbers, keep in mind this kind of dyno reads lower. Sharif says it is not uncommon for a Dyno Dynamics unit to read 8-10% lower than a dynojet under same conditions. He felt the 406rwhp number we hit for stock config was very comparable to the 425-435 numbers we have seen from other GT-R owners' base runs. Also, underpressure confirmed via phone he has seen 406rwhp from another stock GT-R on a different Dyno Dynamics dyno. So we felt pretty good about the base.

The after dynos only revealed a gain of 28rwhp at peak. This hardly stacks up with Cobb's claims of +60hp/+70tq. Even if you figure that is at the motor and take into account 10% for the kind of dyno and 15% drivetrain loss, this would only translate to around 40hp at the crank. What gives?!?!?!?

The answer is simple as you can see from the detailed graphs below. The gains are there, they just are not at peak HP. I have highlighted the **area under the curve** in yellow in both graphs below. Whenever you mod, this is what you really want to know. Peak power is far less meaningful than getting a nice, fat expansion of your powerband.

As you can see from the HP/air fuel graph, the peak HP gain is only 28hp, but the maximum gains (almost throughout midrange RPMs) appears to be right at 60rwhp... exactly as Cobb claims in their advertising for 1.08 / 93 octane / stock tune. More importantly, there is a 40-60hp gain across the power band from 4500 to 6000rpm or so...




Maybe more important than rwhp tho, is rwtq. This is the power you feel and what gets you accelerating. In this case, the biggest gain appears to right at peak torque (approx 435rwtq), but like rwhp there are substantial gains over a wide range, from 3500 to 6000 rpm. And again, as Cobb advertises, the max gain appears to be right at +70rwtq!




Other items of note...
- Air Fuel ratio starts at 13.0 and drops to 11.5 from most of the power range now. Very safe, efficient range for a turboed motor

- Boost was 9-11lbs stock and now runs 10-13.5lbs with Cobb tune

I **hope** this works, but may be limited by bandwidth I have available to host. If someone can grab these vids and post somewhere for share, you have my permission to do so.

STOCK DYNO RUN

COBB 1.08 TUNE for 93 OCTANE DYNO RUN

Finally, with all the work done, it was time to take the redhead out for a spin. So, off the dyno, in the air to have undercarriage covers placed back on, then out into the night...

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Driving Impressions...

OH MY GOD!!!



Prior reports are not exaggerated. This tune really brings the 3.8TT to life. I think the most striking part is the power gains are almost completely in ranges you would use on a regular basis... when you downshift or just need a little extra zip when already rolling.

From a standing launch, the car feels stock.... for a fraction of a second! This is probably good since more power at the bottom end would probably cause traction loss and/or wheel hop, slowing initial acceleration and creating stress on drivetrain. After that initial fraction of a second, tho, the car just pins you to the seat. I mean the GT-R was quick before, but not it is scary fast! It really is like being launched from a cannon now... and mind you, that is without switching the VDC-off... just set everything to R, leave in Auto mode, foot off brake, and hammer the gas. WOW!

From a roll, downshift quick and the car catapults forward. definitely stronger from a roll. For those who remember Space Balls, it is like going from Ludicrous Speed to Plaid.

Nothing I can say here can do the acceleration justice. It's just there, whenever you need, like stock, but now it is amplified. Godzilla really roars with any touch of the right pedal. For the price of the Cobb AP, it is crazy not to buy it. This car continues to astound me. I could not be happier with my purchases (car and Cobb). My GT-R is now at 9500 miles and that number is likely to continue to climb... very quickly.

do you plan to track it now ? just to know the differences


i like your posts. keep them comin

At some point, I will take it to HPDE again. The most like next may be VIR in February. If it's convenient, I may get to a 1/8th or 1/4 mile, but I didn't buy my car for drag racing. so I'd either be out with a car group or just really bored for that to happen.

You did it! Am I going to be one of the last holdout's for tracked cars not running the AP? Nice review.

Nice ride, McDuck!

im uploading them to streetfire
since i wont be around do a search for "mcduck's"

Thanks! just need to drop the links here. My bandwidth is pretty good, but it is limited. Streetfire would be better. I should just start an account there.

Should have come out today

http://www.nagtroc.org/forums/index.php?sh...c=26625&hl=

Streetfire: Stock Run...

Streetfire: COBB Run...

Nice results and a great review of the day you had...

Cheers,
Ben

PS Used the links of Mindlessoath's uploaded versions...

Great review McDuck! The car's looking good!

Excellent write up McDuck! You nailed the Cobb AP experience to the T.

Cowboy

Great review. Good stuff!

Your car is between 500 and 520 whp on a good dyno jet.

McDuck, we now have at least three and possibly four GT-R's all showing the same rwhp. ie. 406 hp.

It's beginning to look like the "stock engines" are SAE rated at ~480 hp. at the flywheel.

This indicates more than the touted 10 percent drive train loss reported by Nissan.

Also, another GT-R was dyno'ed in Atlanta

with the Cobb Access Port mod:

438 rwhp.
451 ft/lbs. torque.

Looks like we are starting to get some real data on the GT-R's

that are being delivered to customers !!!



Hhmmm... seems as though it doesn't always agree with Nissan's PR !!!

I greatly appreciate the honest review on the AP. I would love it if you had any datalogs of the car during those dyno runs. I am wondering why you have a flat spot in the curve...may just be how the dyno is calibrated. You hit the nail on the head with our claims. I tune for power under the curve and not peak numbers...although a nice peak gain is good for advertising...LOL I am able to make good gains with these cars under the curve...the motors come alive with a little more boost, and a complete rework of the timing curve.

The GTR in Stg1/Stg2 form will always have a hard time up top because of the wastegates. They are pushing 80+% Duty cycle for the boost pressures(12.5 - 14PSi) at redline. This is why you will see cars with upgraded actuators making good peak power numbers. Unfortunately, the labor involved in that swap is substantial.

Thanks again, and I am glad to see you are enjoying the product.

John

Great write-up McDuck. Have not gotten the AP but it sounds like it could be fun.

Stupid question - What does it do to your gas mileage?

These are the same vids linked before im just embedding them

mcduck's STOCK DYNO RUN


mcduck's COBB 1.08 TUNE for 93 OCTANE DYNO RUN

and yes the car is rated at 473hp as advertised with 10% drivetrain loss. and your numbers look perfectly fine.

Actually actuactors swap is not entirely difficult. Prior to some who believes you need the drop the enjine to install it? Not true. You only need a tool like cabclick to install it without dropping the enjine. It does involve some patience and time to install it though. At a HKS proshop, it can be done in less then 15minutes.


McDuck, truly awesome review. I like guys who write like you. Clear, concise and clean writings. Gives me a reading pleasure. Also as for your reference, somehere also knew that I dyno my car with Dyno Dynamics. Baseline run is around 385 to 395whp. So what you're seeing at 406 is considere to be very good. Lots of naysayers couldn't even accept the fact that we got 390whps on this Dyno machine initially and call our fuels to the question. IT IS NOT. The dyno IS THAT conservative.

I did my Stage 2 1.08 dyno too and I got 437whp which I would say it exactly the same to yours. Cheers mate! Enjoy it while you can! Run it with HKS 570 kit and Cobbs AP and you'll get over 530whp. lolx

can someone give those of us that are new to aftermarket tuning an insight as to the ap installation? What exactly do you do? Is it hard? Easy? Time consuming?

Thanks

You cant just take any dyno and use it to calculate the drivetrain loss. Dyno Dynamics are VERY low as is evident in his reults. Lower than mustang and FAR lower than dyno jet. That car would easily make 430-450 whp on a dynojet, which surely suggests just the opposite.

Thanks for the comments, everyone! And thanks for getting the vids up on Streetfire.


I've followed Cobb AP's development for months and there are two main reasons I wanted to do it. First, it is a quality upgrade as anyone who has done it can attest. Second are posts like above. It is great to see these guys out on the forum and interacting with the community. Now I have to decide if exhaust upgrades and a custom tune are in my future. ;-)

JOHN: I do not have a copy of the datalogs, but I'm sure if you contact Sharif at Forged Performance, he can probably share that with you.


too soon to tell. I was getting around 20mpg with mixed highway and city driving before and peaking at 24mpg on long trips with lots of highway miles. I'll post new figures in a few days with the Cobb AP tune.


Thanks... I really doubt I'll go with the HKS 570. The car feels great now and I could see maybe an exhaust in my future when prices come down a little, but I think if I start spending a lot of cash I'm going to be looking for weight savings next.


it is not hard. It is slightly time consuming in comparison to other reflashes. Basically you download the latest tune appropriate for your car from Cobb. This goes directly onto the Cobb AP device. You then plug this into your OBD port. First it gives you the option to download your stock/current settings from the car. That takes 30-40 minutes. Then, you upload your Cobb tune to the car (10-15 minutes). Mine took longer because we wanted to get the before and after dynos. As long as you have a good charge on your battery, you are talking less than an hour.

Oh, forgot to mention, we did have a hiccup on the uploads where it was not letting us start the upload of map 1.08. It was simply a result of too much accessory pull on the battery. Turning off the ac/heating system and things were okay. So if you have trouble with the upload due to 'insufficient battery charge' (or whatever message is exactly), try turning off all the accessories you do not need at that time (radio, a/c, polyphonic display, etc.)


what he said. The only way to compare peak numbers on any dyno is to have all the cars you want to compare at the same dyno on the same day. And that only gives you numbers relative to each other, not to manufacturer's claim. I've always looked at the delta between before and after as the only useful power measure off the dyno. Tho, there is a lot of other good info you can log that most people never ask for.

Made me wanna say..."Told you so!"

Welcome to the dark side...now there is no going back seeing what this car can do with minor tweaks.

Hhmmm... Only if you really trust the Dynojet numbers, and in some cases the dyno tech. !!!

Most of us know better !!!


The Big Boys, Katach and others have pointed out the difference between Dynojet & Mustang dyno results for years.

And YES... the Mustang numbers truly reflect the difference between flywheel & rear wheel horsepower !!!

well, regardless of the power numbers, the car's performance speaks for itself. Whether the car is actually putting 400hp to the ground, 450 to the ground or whatever, the proof is in how quick it is. If it is less power, then it is even more impressive that GT-Rs are so quick around a track or in a straight line.

I still can't believe how much more fun the car is with the retune. I'm gonna run out of my warranty mileage sooooo fast, I think.

Congrats. Now get a midpipe in that thing and click over to stage II. The torque at the track is all very usable, resulting in great lap times.

so can i run a stage 2 with a midpipe

Very nice write up!

Question to the forum/Cobb - has anyone done a before and after 91 octane dyno? Also, can the Accessport hold multiple maps so I could have a higher octane track tune when I'll be mixing in 104 unleaded? Thanks.

-Mark

How loud is the midpipe? I know I'm in the minority, but I actually kind of like that the car is pretty quiet.


The answer to the second part is yes, you can store multiple maps and load them as you need them.

man...you want my wheels, I want your AP...you're making me talk to Sharif right now...damn you! lol...

I couldnt agree more. The writeup was a pleasure to read. Thanks Andy! I think we are all very pleased with this simple and inexpensive plug in tune. Based on what we've seen it's a safe, inexpensive way to add significant power/trq to an otherwise bone stock GTR. And with the custom tuning we'll soon be doing, the potential with Cobb is endless.

Thanks for making the trip down, Andy...see you soon.


You guys are going to find out, that our Dyno Dynamics AWD Dyno, is affectionately called the "Heart Breaker" in the 350Z/G35/G37 forums.

No I dont, Mustang is the closest to a factory level dyno we have. Similar to Maha which is supposed to be the daddy of dynos. I think this car would still be 415-435 on a mustang which if it's still a 480 hp car would suggest 10-12%

Great write up....you made me, sitting on the fence, want to upgrade.
Cost of the AP?
Anyone know where to get the install in SoCal?
Any feedback on our 91 octane and the effect of this AP?

Thank you for your time!

Hey John, I will post the boost curve shortly, but most of the dip is a result of the boost falling off. Our dyno plots with very high resolution, and without any smoothing, so it makes the dips look worse than the are...LOL.

AP's are here, and in stock with free overnight shipping. http://www.forgedperformance.com/store/pro...=425&page=1

The duck is in plaid.............nice.

doooooo eeeeet! You'll be glad you did. At this rate, I think our GT-Rs are going to wind up being twins. The funny thing is I had a similar 'separated at birth' experience with my brickyard 350Z. There was a great my350z.com/350z-frenzy member named DrBonz who also had a Brickyard 350Z. Anytime I did a mod, he was thinking about doing it or already had and vice-versa.


"heart breaker"... people gotta stop hinging their day on how high the numbers are and look at the spread. So, Sharif, do you have any pics to share???


I'll shamelessly plug Forged Performance here... give Sharif a call (770-792-0202). I'm sure he can hook you up on the AP. The install is easy. I'm sure I could have done it myself just by following instructions included, but I could not do the before/after dynos in my garage.

great writeup! I was amazed to see how much power you picked up from the AP. Its always great to see a product well worth the money. It was great to finally work with a GTR and we hope to do many more! Let us know if you need anything else ;)

Midpipe adds sound, but the sound in my opinion is well worth it alone. Its not loud at all. Less than my Z06 in stock form. But it add a purrr that is intoxicating.

will installing this cobb acceesport void the warrenty? im thinking of doing it to my gtr but im worried about voiding the warrenty

thanks

Technically, yes, but only if Nissan determines that the warranty issue was a direct results of the flash.

Cobb has taken great measures, to develop a VERY conservative calibration, that is unlikely to cause any engine damage. Remember, Cobb also campaigned their GTR at several Time Attack events as well, and I am sure they were collecting data the whole time.

This is probably the safest power improvement you will ever see.

nice write up! glad to see the results are backed up by users

Ok, if you insist. Here are my lame attempts at photography. I think I will stick to tuning and engine building.

lol Bonz... There's no way you could catch up to him with the number of zaino layers he's got on lol.....

I'm old school on my350z too lol...

I pulled down the boost curve. I kept the resolution very granular, so you can see small changes in boost pressure. This will give you all an idea, of how the boost pressure is mapping. You can see the dip in power towards the end of the run, is mainly a result of the boost pressure falling off a little bit. I think this is where custom tuning really comes into play, in trying to maximize power across the entire power band.