Car runs worse AFTER bolt-ons
 

I bought a G37x sedan last month. Had 13,000 miles on it when purchased.

I started modding by adding an ARK catback. A week later I added a R2C intake. I planned on adding HFC and a tune to finish it off but now I am looking for advice/opinions/flames.

I first added the catback and loved the sound. I felt I lost a little low end power, but gained a good bit on the upper end. Car seemed to pull harder/faster/longer on the top end. 60 mph to 100 mph was much quicker.

Very happy at that point.

Then added the R2C intake.

Now exhaust note does not sound as mean. Car seems to not run as good as with just the catback. Actually it seemed to run better 100% stock than it does with the ARK and R2C now. The car seems to have more throttle response issues than when it was stock, and seems to have more "bog" and "lag" than when stock. The car seems to be "confused".....and so am I. I have had both the ARK and R2C on for 2 weeks now so thecar has had time to adapt/learn. Everything is installed correctly, so that is not the problem.

Like I said before, I want to add HFC and tune.....but I read where HFC can cause even MORE low end throttle response delays. I definately dot want that.

Should I go back to stock?

Should I yank just the intake?

Will adding HFC make the car run better/worse?

Will adding HFC AND tune "pull everything together" and make everything OK??

Will adding a tune BEFORE I install HFC make the car run better?

Is there something wrong with my car??????

The car is "confused" because it isn't tuned for the mods you've done! I guarantee you if you tune it it will run a LOT better, and you will probably see some nice gains.

I'm truthfully not sure about how much difference an HFC would make.

This further shows that intake (and most bolt ons) don't add much performance and actually cause you to loose some (low end). But a tune should help some. See discussion on intake here:
https://www.myg37.com/forums/g37-sed...am-intake.html

Running worse with new add ons.
 

When I had electronics training in the military and we learned troubleshooting techniques, one of the first question we asked is what has changed? In the first case after the CAT back you noticed that the low end torque seemed reduced but the high end seemed better. Often when you have an exhaust system which flows with less resistance, you will notice the bottom end isn't as strong while the higher RPM range frees up and responds better. Very normal and if you like that for your driving, then keep it. If not take it off and go back to stock. You then added a new intake and now it runs rather raggedly compared to the stock. So how do you fix the new problem. Ask your self, "what changed?". The new intake. If you don't like how the car is running, then go back to what it was before you installed the new intake and see if it returns to what it was or as some have suggested get it tuned by someone who has done this before with the parts you have. If that solves the problem, then you can go the next step. If you don't really have the total knowledge of how all these new parts are going to affect the ECU on the car and how it runs, either let someone who does install and tune it for you or don't do it. Also don't try to install two, three or four different mods to the engine and then when it doesn't run correctly, try to figure out what the problem is. Often you'll just be chasing your own tail in trying to fix the problem unless your experienced at doing it which it sounds like your not. Yes you can turn a wrench but can you also tune the car with those new parts? A good mechanic knows when to say "Uncle" and pay someone else who has the experience to do the install and tuning and in the process learns something new himself. I know that's how it works for me. Good luck with this.

Al

P.S. Honestly gentlemen what is this with all the aluminum or metal tubing for the air runners into the intake manifold. Yeah you might not be getting much engine compartment hot air from the air filter assemblies, but what about the metal tubing in the engine compartment once the engine is HOT! Heat is transferred into these tubes and that reduces the charge density which then reduces their efficiency. Why do you think the car manufacturers have been going to plastic resin tubing, and intake manifolds? Because it reduces the amount of engine heat transfer which will affect the intake density to the engine. A good example is the Volvo C30 (which I use to own) which has a complete plastic intake system including all the tubes which bring in the air from the turbo, through the intercooler and then eventually into the intake plenum. The whole purpose of this plastic wasn't just because it was cheap, but also because it kept the intake charge cooler and thus made the engine more efficient in what it had to do. Most of what I see out there with all these shiny tubes is for looks and to make a pretty engine compartment for "show and tell" at car meets. Sadly very few really do the job they promise to do. JMO-ICBW

Intake and exhaust are the utmost simple bolts on and do not require a tune for your car to run right. The car was fine before you added the intake....so thats where you need to start troubleshooting. Determine if everything is on correctly. Make sure you didnt mess up an vacuum lines around the throttle body area...I did this when doing mine and had to do a quick repair because some of the plastic parts in that area are kinda weak. Any check engine lights? Yes, a tune will always help you optimize your performance, but is not required at all with just intake and cat back.

I agree with the above comment. You've added breathing mods and the car probably doesn't know how to handle it because it's set up stock.

One thing you could try is disconnecting the battery for a while, 2 hours at least. Then take it out for a drive. Try to get on it a little when you do. The car may respond differently with the mods you have installed if you reset the ecu.

If you do this, don't forget to reset your windows.

Smart guy sounds smart

might check your MAF sensors too, could have gotten dirty while installing the R2C.

However I think for what you did it sounds normal. I did the same thing on my Tundra, CAI and a catback. Torque was noticeably lower, high end was better, but more than anything all it did was make it loud. You may have gained 10-15hp on the top end, but probably lost the same on the low end. A tune would definitely help as long as it's done by someone competent.

I shake my head in disappointment every time I read one of these threads where someone has modded their car with hardware, then they are confused as to why it runs like crap without a tune. If you change the way ANY engine breathes, you must tune for it. Doesn't matter if it's fuel injected or carbureted... Car or motorcycle... Lawn mower or diesel generator.

i agree it needs a tune,but with those two smiple mods the pcm should adjust after awhile on its own.. try and resetting the pcm.

what type of Fuel do you use?

Exactly! I've posted the same. Plastic absorbs less heat when compared to aluminum. And I believe Silicone absorbs even less.

Anyway - OP good luck with you issue. Let us know how it turns out...

Your car should net some decent gains if you install your HFC and get it tuned. The tune should bring the air/fuel mix into balance along with giving you access to maps that should make the most of your driving style. Logic will hold that if you can shove more air into the engine and remove the exhaust gases with less restriction then the car should perform better. There have been others who have put on similar mods and when they took their cars to be tuned they found out their intake and exhaust set ups were working against each other. This problem can be corrected by tuning but depending on what the set up is certain combinations can put significant power gaps in the rpm range (mostly mid rang) and need to be correct by tuning.

As for aluminum tubing for intakes, I can understand why they use aluminum for long intakes runners but short ones may be more for aesthetics.

OB G is right, the aluminum tubing is a serious heat sink which ends up absorbing a fair amount of engine heat when driving for long periods (the goal is put those air temps on ice :cool::D:cool:)

Anyone who has a long intake CAI (injen, stillen gen 3) I would recommend getting radiant heat shield wrapping such as the one below.


I takes away from engine bay bling but it will at least ensure you are not absorbing all the radiant engine heat and increasing the air temps going into the engine (hot air/ less dense - colder air/ more dense = bigger explosion in the cylinders).

Get the tune, and the HFC, you're car will run a million times better.

you don't need a tune if your only breather mods are exhaust and intake. typically the r2c's are just for noise...not noticeable real gains (not that cold airs yield much either). despite, if you're experiencing delays, i'd honestly check for exhaust leaks. i had a bad gasket the other day, and it delayed throttle incredibly (i thought it was something much more serious). tune will help, but you're barely there. gl.

By no means am I trying to start an argument, but in regards to your comment about metal tubing, I completely agree. However, thinking of cold air intakes (in which is what I thought you were referring to when I skimmed your post), air is constantly moving. If you come home after a quick drive, after warming your engine up...lift and feel the intakes, and you'll notice that it's cold. In terms of short rams, they're purely for noise; most are still placed where the OE filters sucked in air (intakes colder air despite from the grill). Doesn't the same idea apply?

I may have not known what I was doing, but I experimented with my previous car; many headaches and frustrating moments. HOWEVER, if I hadn't made honest mistakes with that car, I would've made them on my current Infiniti. We all need to start somewhere...OP if you're determined to work on your car yourself, GO FOR IT. Just remember..."you gotta pay to play!"