[lordjlam]

Hi Guys, It is pretty embarrassing...

I just raced my friend in his STOCK G37 Couple AT running at "330hp"


I am running a tune with catless downpipes on my N63 AT, running at "500hp"

Both cars weigh roughly the same... BMW @ 3714 lb, and G37 @ 3710 lb.

We did a roll race and after 2nd gear he pulled on me. Some people are saying that Catless downpipes actually lose power, there was a thread but has anyone else / can anyone else back this up? My car isn't throwing any codes, and with my catless dp I feel heavy boost / torque gains

Any suggestions? Aside from "learn how to drive"

I haven't compared it to my own R35, but I had seen a video of a JB4 550i racing a R35 GTR and it kept up with it.. Not sure what is wrong

[Hilly]

Do you have a JB4 Bluetooth device to actually see if your Map/boost is where its supposed to be? I wouldn't think DP would make you lose power.

[lordjlam]

Originally Posted by Hilly

Do you have a JB4 Bluetooth device to actually see if your Map/boost is where its supposed to be? I wouldn't think DP would make you lose power.

Sorry, I should have clarified. I am running a different tune(not jb4), that is supposed to be putting out more power than the JB4 and the company who has done my tune has several dyno data for their power claims.

I agree about DP losing power, and this is what I have read on forums for the N63 Platform.

[badblack550xi]

Originally Posted by lordjlam

Sorry, I should have clarified. I am running a different tune(not jb4), that is supposed to be putting out more power than the JB4 and the company who has done my tune has several dyno data for their power claims.

I agree about DP losing power, and this is what I have read on forums for the N63 Platform.

it's simple run him on 100 octane race gas, also our cars are very fast past 100mph.

[535_BiTurbo]

Originally Posted by lordjlam

Hi Guys, It is pretty embarrassing...

I just raced my friend in his STOCK G37 Couple AT running at "330hp"


I am running a tune with catless downpipes on my N63 AT, running at "500hp"

Both cars weigh roughly the same... BMW @ 3714 lb, and G37 @ 3710 lb.

We did a roll race and after 2nd gear he pulled on me. Some people are saying that Catless downpipes actually lose power, there was a thread but has anyone else / can anyone else back this up? My car isn't throwing any codes, and with my catless dp I feel heavy boost / torque gains

Any suggestions? Aside from "learn how to drive"

I haven't compared it to my own R35, but I had seen a video of a JB4 550i racing a R35 GTR and it kept up with it.. Not sure what is wrong

When did N63 550s start weighing in at 3700lbs?? 🤔🤔

check for boost leaks also....

[bradsm87]

No. Catless downpipes reduce back pressure and gain you power, especially when tuned to best utilise them.

[135i_vs_]

Even stock 550i is faster than a g37. Something is not running right. Downpipes on turbo cars always help increase power, since it frees up exhaust flow.

[535_BiTurbo]

I had a tuned/e85 '15 Subaru WRX, a tuned Mazadaspeed 3 and a FBO 370Z Nismo pull on me after 90mph. I made a post awhile back regarding why my turbos sounded like a high pitched blower at high rpm and the top end was severly weak. There was no power after 5k, I had to short shift just to keep power on.

I checked for vaccum leaks and found a cracked/detached crankcase breather hose on the passenger bank. I R&R'd that and still had a loss of power. Went even deeper on inspection, checking the vaccum lines and found a completely severed driver side bank turbo wastegate hose that runs from the turbo wastegate up and down under the alternator to the vaccum assembly behind the passenger watercooler/intercooler. Replaced that hose and now I have full power, turbos comeon much sooner and the turbos do not whine at high rpms anymore. Pulled a '16 392 Charger on the highway, put several cars on a '15+ Subaru STI RA and a modded '16+ 5.0 couldnt reel me in on the highway. Check all your vaccum lines

[warpeacelove]

Originally Posted by badblack550xi

it's simple run him on 100 octane race gas, also our cars are very fast past 100mph.

But why should he have to run him on a higher octane especially for a Stock G37.

He should be whopping him from a roll or dig especially when he has more power and torque stock for stock unless he is having a boost leak.

The OP should get his car smoke test and dynoed.

http://www.bimmerfest.com/forums/arc.../t-746487.html

[lordjlam]

Already booked an appointment with my shop next week Monday. Thanks guys. Just wanted to figure it out / get an idea what may be the cause.. Pretty damn embarrassing to lose to that. It's not throwing any codes either, Would any of the issues 535 is explaining throw codes?

[535_BiTurbo]

Originally Posted by lordjlam

Already booked an appointment with my shop next week Monday. Thanks guys. Just wanted to figure it out / get an idea what may be the cause.. Pretty damn embarrassing to lose to that. It's not throwing any codes either, Would any of the issues 535 is explaining throw codes?

I never threw any codes either when I had a leak, car ran just fine, only issue was the lack of top end, slow turbo spool, slow revving, etc. I posted a vid awhile back of the issue.

[135i_vs_]

Originally Posted by lordjlam

Already booked an appointment with my shop next week Monday. Thanks guys. Just wanted to figure it out / get an idea what may be the cause.. Pretty damn embarrassing to lose to that. It's not throwing any codes either, Would any of the issues 535 is explaining throw codes?

You will rarely get codes for vacuum leaks. These things require visual inspection.
N63 runs hot, causing premature deterioration of rubber parts.

[550Reasons]

Lol my stock 550 was faster than my old G37 by quite a lot, and after DPs and tune I was hauling ass into the low 12s

[lordjlam]

So turns out, I am misfiring in 7/8th cylinder
Theyre gonna change my coil packs on Monday and I also have a broken Breather hose. Im hoping that should be the cause of low power.. or do you guys think there could even be anything else or is it the tune?

[135i_vs_]

Originally Posted by lordjlam

So turns out, I am misfiring in 7/8th cylinder
Theyre gonna change my coil packs on Monday and I also have a broken Breather hose. Im hoping that should be the cause of low power.. or do you guys think there could even be anything else or is it the tune?

That is more than enough problems for your car to be running sh*tty.
You can't suspect a tune when your car has mechanical issues.

[lordjlam]

Originally Posted by 135i_vs_

That is more than enough problems for your car to be running sh*tty.
You can't suspect a tune when your car has mechanical issues.

Haha! Theres always atleast ONE problem with the car at all times, am i right?

Im just worried as 535 said, the breather hose wasn't even causing his issue.

[135i_vs_]

Fix these problems and monitor boost pressure. Also check for BMW codes. I use carly app for this. These are not much worst than other 400hp cars :-)
I drove mine 151 mph no issues, ran Mustang GT (such a close run), Charger R/T (close run) on different days. Car has been consistent with performance so far.

I will be tuning it next week to be more "competitive". Seems like many newer cars have ~ 400hp these days...

[winjury]

Originally Posted by lordjlam

Hi Guys, It is pretty embarrassing...

I just raced my friend in his STOCK G37 Couple AT running at "330hp"


I am running a tune with catless downpipes on my N63 AT, running at "500hp"

Both cars weigh roughly the same... BMW @ 3714 lb, and G37 @ 3710 lb.

LOL. your 2012 BMW 550i xi weighs 4500lbs...not 3714. So close. Where did you even get that number??

[550iFreak]

You sure the g37 is actually “stock”?

Lol