CSL airbox vs throttle response/low rpm torque

[Ramps]

My old setup was k&n intake, pulleys, full Supersprint V1 headers, cats, twin pipe and street muffler. Stock tune did 316whp. Last summer I did a Karb csl air box, map sensor, hp dme, and HTE tune and the car is way faster everywhere. I didn’t have time last fall to redyno, i will this spring, but i have way more low and midrange than I did before, i even checked the tune to see if he had tweaked the throttle map to fake more mid-range under part throttle and he didn’t, the throttle map was the same as stock, just more power everywhere. Smooth, no bucking or hesitation, better idle, no downside.

I think if ppl are losing low end or drivability with an airbox it’s gotta be the tune or lack of a MAP or good exhaust flow.

[Sharocks]

Modifying an E46 M3 with NA mods and caring about usable torque is laughable.

I have an HTE Alpha N tune on my car. It works fine and it's smooth.

Also, if you're cruising around at 2500 rpm, uh why?

Lastly, keeping low end torque is all about what parts you throw at it, for example, I used SSV1 headers and I picked up torque.

[giOsaurus rEx]

Bumping this.

I'm debating whether to get a Karb CSL style airbox. I talked to Active last year and they recommended not doing this for a street car as low-end torque in cruising RPMs will suffer, saying the car will feel broken at 2500 RPMs. I'm guessing they used canned Alpha N tunes.

All these forums, including m3cutters, suggest that the MAP route is the way to go. However, I still see posts on here where users are complaining about drivability hesitation even on the MAP sensor'ed tunes. Randy at Epic is local to me and he suggested Alpha N is the way to go. I'm having a difficult time comparing users' dyno charts when most runs start at 3000 RPM or above. I care more about low end torque (below 3k) than high RPM horsepower.

[Gt4]

Ok so here are some news about my friend’s car I had 2 months ago. His tuner worked on the tune after my feedback. What I didn’t knew is it was just a base map to get the car working with the CSL airbox but nothing more. So last month he spent some times tuning it for real!

My friend went to do some dyno runs with the car couple days ago. The car has a Turner CSL airbox, Euro headers, Euro cats section1, single 3’’ Supersprint straight section 2 and a SS Sport muffler. And an Alpha-N tune. Here are the numbers, seems like a healthy engine to me

[Kdubski]

Just had HTE tune my car (non dyno) for a karbonius box w/map sensor conversion. For some reason the throttle is extremely weak, almost like limp mode, although it does rev up to red line. In Sport mode, the car feels a bit more normal. We're going to dig deeper next week to try to figure it out, but for the time being has anyone experienced something similar?

[Bry5on]

Inconsistent (sometimes great, sometimes laggy, sometimes basically nothing) rev matching behavior here as well, seems to be limited to rev matches that blip from anywhere between 2-3k where all the resonances are. Same issue with PCS and HTE tunes. My data logs showed all sorts of resonance behavior around those RPM ranges that neither tuner had tuned flat at WOT and definitely not in part throttle.

My setup is CSL DME + flap + MAP and SSv1 headers and section 1. I’m betting that the headers have enough of an impact on moving the resonant responses of the engine that they throw the CSL tune out of whack, especially when combined with not-CSL cams.

Ultimately I had to do the WOT tune myself and by changing the interpolation target RPMs I was able to get a flat AFR response all the way down to about 1500rpm.

DIY part throttle tuning up next, probably going to need the same treatment.

[chapmans]

Yeah that's my main complaint is inconsistent blip behavior when rev matching.

[LSBNick]

I can attest to this a bit. HTE tune on alpha N with karb box. Tune was done in October 2021 in a less than adequate shop setup, in about 90 degree climate. In cold climates, the car performs at 110%. Smooth throttle engagement, revs like a MF, etc etc.

When summer time comes around, the car definitely requires way more throttle input to get moving, specifically from dead stop into 1st gear. Very occasionally, will I go to heel-toe revmatch and either get not enough response, or nothing at all. It happens so rarely that I really don’t care enough to look into it further. At this point the car has functioned well enough to the point where I can’t justify the other $1k-$2k cost it would be to convert to a CSL map tune (especially since HP DMEs go for $800+ now for some stupid reason).

Also important to note, HTE has tuned my car twice. Once with the TMS V2 box, and again with the Karbonius (there were other exhaust modifications done as well). On both setups I’ve had similar experiences.

Perhaps in the future I’ll have HTE take a look at the car again and see if he notices anything out of whack, but so far it’s not a consistent enough issue for me to dig deeper.

[siamkazi]

Hassan recommended the Alpha N for me as opposed to going the MAP route (and did a solid job fine tuning the drivability). The car rips.

[tlow98]

Yeah I have map sensor and CSL dme conversion. It doesn't have rev hang per se, just doesn't rev as quickly as I would expect considering the mods

I would think 288 cams would make it slower revving low in the rev range and faster at the top? Just spit balling here…

[chapmans]

Do you have the HP DME?

Yeah I have map sensor and CSL dme conversion. It doesn't have rev hang per se, just doesn't rev as quickly as I would expect considering the mods

[usdmej]

my engine blipping and low speed throttle is still way worse than my 987 Boxster S. It's always baffled me why it isn't better

rev hang is definitely a tune related issue

[Slideways]

I have an evolve airbox, PCS tune, light flywheel, 288 cams and my engine blipping and low speed throttle is still way worse than my 987 Boxster S. It's always baffled me why it isn't better

Do you have the HP DME?

[chapmans]

I have an evolve airbox, PCS tune, light flywheel, 288 cams and my engine blipping and low speed throttle is still way worse than my 987 Boxster S. It's always baffled me why it isn't better

[tlow98]

My throttle response is great, evolve alpha n tune from 2017. Car is an explosive beast.

fwiw, my experience was the opposite with evolve + alpha N. Boggy, and mostly just felt slow to respond all over. CSL tune and map sensor improved it, but then I had a low rpm bucking/stutter.

this was back in 2014 tho. Sounds like tunes have come a long way since the.