full bolt on 17t n54 only getting 360 horsepower

[kronk_5]

ive got a 135 with an n54 with relocated intakes 17t turbos 5 inch intercooler aluminum charge pipe and catless downpipes and am not making as much porer as most other people seem to be making. only 360 at the rear wheels and im not sure what im doing wrong.

ive made sure everythinhg is ship shape mechanicaly no boost leaks no sensor issues no vacuem leaks all working as its suposed to be. no codes other than for the cat delete and the upgraded fule pump.

i was on mhd and the car felt amazing but kept complaining about fule trim. i pulled spsrk plugs snd they were white so i took it to a local tuner to get it running right. he switched me over to cobb and it feels like i lost a hundred horsepower.

when i bought the car in arizona at nearly sealever it ran fine no codes i brought up to where i live at 5000 feet above sealevel and it started complaning.

so my question is, is the switch from mhd to cobb costing me the power or is it the altitude limiting the engine.or both? or am i delusional and 360 on pump gass is normal?

any information on this is super helpfull thanks in advance

[drover135]

I think your answer is in your question. “My tuner switched me from MHD to Cobb and I lost a hundred horsepower.” Altitude is not going to make you lose 100 hp. Maybe a handful, sure, but not 100. Just switch back to the MHD tune and see if the power comes back. If so, stick with that tune and investigate your trim issues within it rather than switching tunes completely

[kronk_5]

so the issue was with the previous tune not asking for enought fule and the ems having a fit about running lean and triming fule in to compensate. with the new tune I only ever got one trim code at 9000 feet, so the trim seems to be altutude dependent to me. it seems mhd is the way to go but id need a custom tune for the altutde since the ots map had the issues with the trim codes at 4000ish feet.

so i guess the next question is where can i get a good custom tune on mhd so im safe at the altudes i live at?

side question does anyone have a good understanding of why mhd can get more out of the car than the cobb can?

[PerformanceEngSolutions]

I would talk to Ken at Wedge Performance since he created the OTS MHD maps for the N54. He’ll be able to remote tune your car by sending you different maps to try. In my experience he’s been very responsive.

The difference between brands is the tune itself and the boost and timing that each tune is running. What boost are you running at on the Cobb map compared to the MHD map?

Fuel octane makes a big difference for timing. What fuel did you use when you got that custom Cobb map?

[kronk_5]

so i dont know all the details on the mhd stuff it was on since that was done by the previous owner. when i used a data reader it was hitting 18 psi from 3k to about redline.

when i took it to the tuner for the cobb he put it on the dyno and sais the most he could get before it started pulling timing was 12 pounds. he was able to get 15 on 98

so wass the mhd just super dangerous running 18 on 91 or is cobb just bad at being able to safely add boost. i never had heat issues or misfires on mhd just ran lean. what is the normal boost target for mhd on pump gass for these mods?

[PerformanceEngSolutions]

Originally Posted by kronk_5

so i dont know all the details on the mhd stuff it was on since that was done by the previous owner. when i used a data reader it was hitting 18 psi from 3k to about redline.

when i took it to the tuner for the cobb he put it on the dyno and sais the most he could get before it started pulling timing was 12 pounds. he was able to get 15 on 98

so wass the mhd just super dangerous running 18 on 91 or is cobb just bad at being able to safely add boost. i never had heat issues or misfires on mhd just ran lean. what is the normal boost target for mhd on pump gass for these mods?

I think that’s your answer, you’re currently running 12psi, which correlates to around 360whp.

I’m running the Stage 2+ 91 octane map right now but even on 93 pump gas i had heavy timing corrections. To deal with the timing corrections I started running E30 which cleared up the corrections.

It seems like fuel octane is junk these days so I’d recommend running E30 and I’m confident you’d be back up at 18.6psi boost that the Stage 2+ maps target without timing corrections.

[PerformanceEngSolutions]

But then again I’m not sure how your Cobb tuner would only be able to run 15psi on 98 octane. He probably needs to turn the timing down below whatever baseline he’s using.

How did he get 98 octane did he use race gas? Also what are you running for plugs and coils?

[kronk_5]

we were using octane booster to get to the 98 and yes he seemed to be timing limited from what i rember him saying

so it sounds like the move will be to get back on mhd, get someone to e tune it so its safe at the altitude, and make a switch to e30 so that it can run more boost and timing.

what sort of numbers should i be looking for on mhd stage 2+ on 91 and e30 so i can make sure it is actualy the tunes and not something mechanical not preforming as it should

[kronk_5]

im running whatever fcp euro recomends i think its ngk iridium and delphi coils

[PerformanceEngSolutions]

Originally Posted by kronk_5

we were using octane booster to get to the 98 and yes he seemed to be timing limited from what i rember him saying

so it sounds like the move will be to get back on mhd, get someone to e tune it so its safe at the altitude, and make a switch to e30 so that it can run more boost and timing.

what sort of numbers should i be looking for on mhd stage 2+ on 91 and e30 so i can make sure it is actualy the tunes and not something mechanical not preforming as it should

I heard octane boosters don’t work as well as they claim and the one I used (Gold Eagle 104+) barely helped my timing corrections. If you make an E30 mix with 93 octane as your base you’ll be at an octane rating of 98.6, which is what cleared up my timing corrections.

From what I understand, when you increase boost you also need to decrease timing. So for example if an NA engine can run at 23 degrees of timing stock, a boosted engine will need to run 15 degrees of timing. It’s counterintuitive but I’m assuming your Cobb tuner wasn’t decreasing timing accordingly when increasing boost.

On 17t’s you should be able to push 22psi of boost, which would land you somewhere in the 500 whp range on pump gas (someone correct me if I’m wrong).

I recommend working with Ken at Wedge Performance as he created the OTS MHD map for the N54. He only tuned N54s and so he has a very good handle on how they behave and how they should be tuned. What he’ll do is send you a base map and tweak until both of you are happy with the outcome. He could send you as many as 10 map revisions before you’re finished.

[kronk_5]

haha ok the tuner asked me if i was looking for a specific number nad having heard 17t's were good for 500 so thats what i ased for he laughed at me and said no way

[darkrom]

Who is this tuner?

I think you downgraded to a worse platform and tbh it sounds like a bad tuner but we may not know the whole story.

[PerformanceEngSolutions]

Originally Posted by kronk_5

haha ok the tuner asked me if i was looking for a specific number nad having heard 17t's were good for 500 so thats what i ased for he laughed at me and said no way

The issue is that he’s not able to get your boost running above 15psi. You should be able to get up to at least 22 psi with 17ts. If he’s not decreasing timing then yea he won’t be able to get above 15 psi as the car is already pulling it by itself.

At 15 psi you should be around 370whp but since you’re at 360whp I’ll blame that on your altitude ( I’m contradicting myself from an earlier post but 360whp at 12 psi is incorrect)

Unless you want to ask him more questions to try to resolve why he can’t get your boost up to 22psi then I’d look for a tuner with N54 experience.

[wheela]

OP, do you have any logs you can share? What/how old are your injectors? Unless there's something wrong with your MAP sensors, I don't l don't think altitude explains your fuel trim issues.

You'll have to post some logs for review so people can see what's going on and give better advice how to proceed.

[kronk_5]

he did say the car was pulling timing at anything past 15 but the car wanst having any knocking issues on the previous tune at 18 psi and wasnt pulling timing there so im not sure why it was for him

and from what i can tell my injectors are pretty new they are index12