AadosX

iTrader: (10)

Right now I have intakes, test pipes and exhaust on my HR. Sometimes when I'm getting on it, but without even going WOT, I notice spots in my powerband where the power will actually decrease a little bit. I can actually feel it, that's how noticable it is. Don't get me wrong, it isn't night and day.. I don't think a passenger would feel it.. but because I'm driving and paying attention, I can just notice it.

Is it safe to say that this is just because I need a tune?

It has happened at least twice now. Once it was just a small hiccup around 6000+ RPM's or so in 4th or 5th gear (I forget). Then last night it felt like it went for a couple hundred RPM's around 4500 in 2nd or 3rd.

It seems very weird to me and it almost seems to be getting more frequent, but that could just be coincidence or that I'm driving my car harder lately. It's also getting very hot here.. if that matters.

The main thing that confuses me is that I thought our cars were open loop and MAF based tune when not full throttle, so I didn't think my bolt-ons would make it run rough unless I was WOT (closed loop).

Thanks,
John

bmccann101

iTrader: (16)

absolutley and completely.. YES.

Your AFR is leaned and all over the place.. the MAF readings are probably all over the place...

a tune will fix EXACTLY this.. and btw... lets be honest, all those bolt ons never really even seemed to make your car any faster did they?

Tune it, and see what happenes.. its like a light switch turned ON for all your mods.

bmccann101

iTrader: (16)

oh and i notice that at right at 90 degrees outside temp or under, the car drives quite different. Much better. Smoother, more linear, snappier. Less noise.

its the same every year.
summer driving sucks, hot air is terrible to intake.
plus they give us crap gas in the summer..

AadosX

iTrader: (10)

Yeah summer driving really does suck. I can notice a huge difference even between a summer day and summer night (95 degrees vs 85 lol).

AadosX

iTrader: (10)

I have seen you rave about a tune before haha, I am hoping that will be the case for me. It will still be a few months before I can afford one though unfortunately.

I will say that I did notice some from the mods. I didn't install them all at once, but the test pipes, I can definitely feel. Not so much WOT (racing), but partial throttle there is a huge difference. Hopefully that difference will be there at WOT as well once I'm tuned.

I'm not trying to sound arrogant or like a know-it-all, but from what I've read and experienced, the HR's are quite different than the DE's, not just from a power stand point. I don't think that tuning is the same for both, as in, for now, I have a hunch that HR's came tuned very rich from the factory. I have hooked Cipher up to my car and it is actually still running pretty rich with all of my bolt-ons. Rich? yes.. but of course the A/F's are all over the place and not really smooth. So I agree it certainly needs a tune. It's just the whole open loop vs closed loop and when thing that has me chasing my tail.

Either way, I can't wait for a tune. I just don't understand why at partial throttle I'm getting this issue if it's open loop. Maybe it's just the weather.. =/

P.S. Thanks for the reply.

djamps

iTrader: (1)

HR or DE... doesn't matter, both respond similarly to a tune. Both need to be tuned to unlock the potential of your bolt ons. If anything, it's more important to tune your HR because it's already tuned 'on the edge' and more sensitive to bolt ons messing **** up. My friend could barely drive her HR after installing intakes, headers and HFC's. After several failed attempts to fix things at the dealer, a visit with the local Uprev tuner got things running just right.

bmccann101

iTrader: (16)

yep, aside from a different plenum collector, the HR gets its extra juice from different EECU tuning and timing and two intakes. etc. I also heard they dont respond as well to bolts on .. but fear not, get your tune and you"ll be saved.

I gotta be honest, i just bought a used COBB AP ( btw theres a few DIRT cheap like 250 bucks in the classifieds right now grrrr..they may be HR application models as they are far more common than the AP for DE, check it out...) and ran it myself, stage 2 plus, took 30 minutes...and advanced timing 2 degrees, im sure its not as good as a full rpm by rpm osiris tune, but holy crap, what a difference.

AadosX

iTrader: (10)

What makes you think this? I must respectfully disagree, though I could definitely be wrong. But from what I've seen, the HR's respond better to bolt-ons powerwise than DE's (untuned), however DE's respond better to a tune when they have bolt-ons than an HR does in the same situation. I believe this is because HR's are in fact tuned richer from the factory, giving them more headroom for bolt-ons. Like I said, my car is actually still running rich even with my bolt-ons, whereas I have heard horror stories about DE's being very lean with bolt-ons.

And more importantly, if Z's are open loop under partial throttle, then bolt-ons shouldn't throw off the tune at all as long as the MAF area diameter doesn't change. The ECU should be able to read the additional air coming through the MAF and give more air to compensate for it. However, if they are closed loop under WOT like I've read (not sure if that's right or what..), then of course they would need a tune to reprogram the tables for maximum WOT performance.

But alas, as they say, every car is different so maybe my experiences are isolated..

djamps

iTrader: (1)

Adding/subtracting fuel will give at most 5whp give or take -- and adding fuel will actually reduce power without adding timing -- and maximum power will always be around stoich. It's timing where the power is unlocked, so regardless of rich or lean from the factory (and I've seen rich DE's) it is somewhat irrelevant to what kind of power can be unlocked.

AadosX

iTrader: (10)

They have higher compression as well.. there are a lot of reasons they got a bump in power. Like I said, I believe that their power could be greater from the factory than it is, and my speculation is that they tuned the engine *less on the edge* because it was a new design or something and didn't want a lot of warranty issues.

I mean, honestly man, they definitely respond just as well from bolt-ons I would say. Intake, test pipes and exhaust and a tune and you're looking at 30+ rwhp. I'm not sure how DE's are but I can't imagine it being much more from those same mods. Keep in mind that we have no aftermarket plenum options so you can't consider that when talking about DE gains from bolt-ons.

I do appreciate the help though, I'm not trying to sound like an *** here..

Yeah I have considered the Cobb AP a few times to hold me over but the whole disclaimer they have about not using it with aftermarket intakes sort of scares me away.. =/

bmccann101

iTrader: (16)

Curious.. how are you getting this data? If youre sure your rich, like at 10-11 etc... then i suspect the majhority of the tune benfit will come from adjustments to MAF readings. Air volumes, patterns etc... That made a large change in the way my car ran. If youre dead certain that your AFR is on point ( rich sucks to btw, you lose power) then still know that a tune will surely fix your problem.. i know my tst pipes were like an on off switch at 3500 rpm before, now the torque is vastly increased, and the power delivery is VERY linear, a large change from before... my car used to act one way at idle, one way at top end, and another in third gear passing people at 4500 rpm... was jsut weird.. kinda ruined the experience of driving the car.. my tune brought it ALL back for me.

Yes, i do rave about the tune/reflash... i literally had NO idea it was that dramatic.

Good luck my man. get that tune.

AadosX

iTrader: (10)

Good point. I suppose timing could be the real culprit here.. which would definitely make sense because I bet my car is pulling it like crazy in this heat.

AadosX

iTrader: (10)

I hooked Cipher up to the car with only intakes and exhaust, and then with intakes, exhaust and test pipes. Even with the test pipes I am still running rich. I will find the exact thread with my numbers in a bit and put a link here. And yeah, it's still TOO rich lol, need to lean it out even more IMO with a tune.. plus timing and all that other stuff that I know little about lol.

I appreciate it man! Can't wait to get that tune myself and go whoop up on some 335i's!

Boosted 350z

I got a question, you say that it happens not in wot, but it was @ 6,000+rpm in 4th or 5th. What are you doing at 100+mph speeds without wot?

AadosX

iTrader: (10)

Because I'm not tuned right now I try to never go WOT.