Will our cars accept mods or is a tuning flash required?

[1080Rider]

So, I've been doing some reading and I'd like to do some sort of intake and maybe exhaust to get another 15-20 hp out of our motor. I know that some cars today need a complete reflash to change any parameters of air/fuel mixture and to increase performance? Is the M37 one of those cars or will an intake make an immediate impact without a tune? Obviously if you're doing a full exhaust or changing cams you're going to need to change the computer software, I'm just wondering how far you can go on these cars before you have to change the computer...
Thanks in advance!

[DKASM37]

The short answer would be that you won't gain anything from those mods without re-flashing the ECU with software such as Uprev on these cars. This topic has come up numerous times so I would suggest searching this forum for more detailed info.

[1080Rider]

I've been reading these forums for the answer but the info is usually buried in a post about a different mod... In any event, I was reading the G37 forums and they seem to think intakes and cat-back exhausts are giving them hp gains. I can't imagine the two operating systems w/ the same motor are so different that one car would benefit and one wouldn't. Are they imagining things (the placebo affect is easy to get) or can we get a hp out of some mods? Just looking for some info from people that have installed some parts and see if they noticed any difference.

[Ilya]

I've been reading these forums for the answer but the info is usually buried in a post about a different mod... In any event, I was reading the G37 forums and they seem to think intakes and cat-back exhausts are giving them hp gains. I can't imagine the two operating systems w/ the same motor are so different that one car would benefit and one wouldn't. Are they imagining things (the placebo affect is easy to get) or can we get a hp out of some mods? Just looking for some info from people that have installed some parts and see if they noticed any difference.

As DKAS said, a proper search (not just a 1 minute quick glance) will yield great results. Because something is buried in a thread for another mod doesn't mean it isn't worth reading. To get a full understanding of what you need to do to achieve your results, you will need to spend hours upon hours reading. Your questions won't be answered in 5 minutes by search or any particular member. Don't take that the wrong way...take it as constructive criticism. This topic has been covered:

This will be a start: uprev-engine-management-system-discussi ... 04375.html

The general rule of thumb that mods *might* give you performance benefits but they will *NEVER* be fully realized without a matching tune. If an exhaust is rated to give 8-9HP, without a tune you might only get 1-2...or placebo. Or in the case of intakes, especially cold air intakes, you'll likely lose power due to heat soak (in most applications).

If you want to build your car properly, you ALWAYS need to tune. Period. Across the board. That isn't up for debate. If you can't afford to tune your car, you'll only get like 20% out of your mods (or whatever number it is). Honestly, it's a waste to mod a car without a tune. Unless all you mod is suspension and wheels.

[1080Rider]

No, I get it, I wasn't trying to be an a** either. I've done a lot of reading and I still had the question. I decided to just ask it clear and concise so it is out there. I have read that exact thread you linked, it still didn't give an answer to the conflicting info. G37 guys are saying they're getting results and M37/56 guys are saying you need uprev. I was just seeing if anyone out there had an experience where they added and intake and felt a big difference. I've even read the posts on here about intakes and there wasn't a definite statement that it made a huge difference.

I've had different experiences w/ different cars, I've had cars that no matter what you do, the computer won't change parameters and you need to reflash the ECU and I've had other cars that love mods... I'm not looking to do a bunch of work to my car. But w/ a dual intake system, if the computer would recognize it, it seems an intake should do a lot to get more air into the engine and increase hp. Thanks again to everyone passing on their knowledge in this thread and all the others!

[wideopn11]

I have stillen exhaust and just did Takeda intakes today. I can def feel a difference at full throttle. I don't know how much actual power increase it is yet...hence I'm looking into getting an Uprev tune on a dyno soon. I'll def be posting before and after numbers to see how much the tune helps.

[1080Rider]

Thanks wideopn! Exactly what I was looking for... one question about the exhausts people are installing. Are they any bigger? Or are the gains reached through better mufflers? I ask because on my old mustang and volvo V70R gains were only realized through a bigger exhaust. The stillen exhaust doesn't mention that it has a bigger diameter for better air flow, so I'm assuming it's the same size as stock, just better flowing mufflers. If that's the case, a hi-flow cat and muffler combo would probably be the best since increasing the diameter doesn't seem to be an option (although, hi-flow cats are usually pretty spendy).

[PostalsQ]

Rider, I did Stillen at 1st. Felt like I lost low end. Gained a tiny bit on top. Most notable difference was sound. Like the new rumble. Not obnoxious either. Then since Stillen doesn't make a true catback. Went with Motordynes xyz Y pipe. Excellent quality btw. Difference. Slight difference in sound. Deeper. I went with a resonated Y btw. Power wise. Again. Same, very minimal. Felt again a tad bit on top end. Then went Injen long tube CAI and HFC's. Again felt minimal gain. It felt like after 3-3500 rpm wakes up & moves. Then went with my Z1 intake manifold & plenum. Really felt no difference on that. Finally. Got the Stillen UD pulley. Felt like I got some of my low end power back. And I've still never tuned her. She will benefit from tuning. It's not so sensitive that you require tuning. But it definitely will benefit you to tune. I'm still avoiding tuning as I'm trying to get the time to add my shorty Z1 headers and new HFC's. Then I'll schedule a tune asap.

In regards to exhaust. This is only my opinion btw. I think and will probably do a custom Y pipe to Stillen exhaust. It all necks down to a single exhaust pipe in the mid section. I'm thinking of cutting and creating a dual pipe in that same section. But I think 2 extra resonators will be needed to avoid that horrible rasp.

[1080Rider]

This is super helpful! I had a similar experience w/ my old mustang. It was an 88 so the computer interference was minimal. I did an intake and got great gains across the board. I did a 2.5 inch cat back exhaust (up from 2.25 I think) and felt like I lost quite a bit down low, the thing is though between the exhaust and intake, the top end RIPPED! It was like a two-stroke w/a powerband so it was great in the end.

I really like the torque in my car now so I don't want to lose much of that. I will keep the same diameter of pipe but maybe try to free up the airflow by doing better mufflers. There's a custom exhaust shop right by my house, they can do anything you want... you're info is great! Thanks!!!

BTW- you're doing a great job on your car. Really cool to hear about it. It's funny, I did almost the exact same things to my old mustang. UD pulleys, exhaust, intake, strut tower brace. Was about to do an intake manifold before I sold her. That thing screamed!

[PostalsQ]

BTW, I remember someone here gave great advice on the mods. You may be doing more damage to your car after without tuning. So the computer I'm sure is trying to compensate for the extra breathing. And I've noticed and smelled that the car seems to be running rich. Which is not good. I think it might be the culprit to my SES light popping up. And I suspect maybe the rich condition did something funky to the sensor. And then a torque converter was suggested to me. Which I agree with. But damn if they're not money!!! So after headers. I'll think about getting the level 10 valve body. Cause rebuilding this trans is not in the budget.

[Ilya]

BTW, I remember someone here gave great advice on the mods. You may be doing more damage to your car after without tuning. So the computer I'm sure is trying to compensate for the extra breathing. And I've noticed and smelled that the car seems to be running rich. Which is not good. I think it might be the culprit to my SES light popping up. And I suspect maybe the rich condition did something funky to the sensor. And then a torque converter was suggested to me. Which I agree with. But damn if they're not money!!! So after headers. I'll think about getting the level 10 valve body. Cause rebuilding this trans is not in the budget.

IIRC, car (at least the V8) runs a little rich from factory so when you add parts you're making that even worse. I know my back bumper had the black 'soot' from all this horsepower...once I got tuned that condition subsided quite a bit. My rear bumper was recently repainted and after a week, no black soot yet lol.

[PostalsQ]

There you go again Ilya. You V8 guys bragging about all that HP someday I'll catch up to y'all

[DFW2011M56S]

BTW, I remember someone here gave great advice on the mods. You may be doing more damage to your car after without tuning. So the computer I'm sure is trying to compensate for the extra breathing. And I've noticed and smelled that the car seems to be running rich. Which is not good. I think it might be the culprit to my SES light popping up. And I suspect maybe the rich condition did something funky to the sensor. And then a torque converter was suggested to me. Which I agree with. But damn if they're not money!!! So after headers. I'll think about getting the level 10 valve body. Cause rebuilding this trans is not in the budget.

IIRC, car (at least the V8) runs a little rich from factory so when you add parts you're making that even worse. I know my back bumper had the black 'soot' from all this horsepower...once I got tuned that condition subsided quite a bit. My rear bumper was recently repainted and after a week, no black soot yet lol.

Believe it or not my car was actually running very close to the factory air/fuel ratio targets even with the HPS Intake Tubes, K&N filters, and 2.5" X-pipe setup. Cutouts opened leaned it out about 0.3:1. Factory air/fuel ratio targets were high 10s and low 11s at WOT. Cutouts open I was running 11.5:1. I now target 12.46:1 and it runs great.

[armybrat]

Believe it or not my car was actually running very close to the factory air/fuel ratio targets even with the HPS Intake Tubes, K&N filters, and 2.5" X-pipe setup. Cutouts opened leaned it out about 0.3:1. Factory air/fuel ratio targets were high 10s and low 11s at WOT. Cutouts open I was running 11.5:1. I now target 12.46:1 and it runs great.

I have the same intake tubes and exhaust set up (minus the cutouts). Stock tune. I am using the stock filter boxes and ram air plenum, but I drilled a series of holes in the filter boxes to simulate the Eventuri ram air intake system I saw on the Audi R5 someone posted in another thread.

I haven't checked any A/F numbers, but there's no visible difference in the soot accumulation that would indicate any viable changes because of adding the intake hoses and changing the exhaust.

I've been wiping my exhaust tips at the end of every driving day since I've had my car (Oct 2015).

There's simply more soot to clean off in the colder months because cold air is more dense, and the engine works harder to push it out the exhaust pipes, especially during a cold start. It also stays in open loop longer in colder weather...all of this causes the car to run richer (more soot). In the warmer months, there is very little soot to wipe down. My stock 2007 Acura MDX did the same thing.

I do agree that the car runs a little rich from the factory, but adding the mods didn't seem to affect my A/F ratios and soot residue.

[1080Rider]

I have the same intake tubes and exhaust set up (minus the cutouts). Stock tune. I am using the stock filter boxes and ram air plenum, but I drilled a series of holes in the filter boxes to simulate the Eventuri ram air intake system I saw on the Audi R5 someone posted in another thread.

I have looked at the intake very briefly, but this spring I plan to open up the boxes a little and maybe see if I can put some conical filters in them. We have a type of cold air setup already so w/ a little modification it seems that we might be able to improve upon a decent design from the factor. I'll look around for the post you referenced above. It's cool to find out that others have done what I was planning...