MB

Depends how many bolt ons imo. If you have too many, a plug and play ECU may not be able to cope fuelling wise, as they tend to be mapped for certain mods... Then you need a standalone. But I do agree with your point for a few breathing mods.

There are mappers out there for AEM too, the S2000 isn't anything too special in that regard.

Nabu

I do understand the rationale behind this part but do you have any effective proof to support that statement.

Maybe indeed its common knowledge, i just would like to see how lean it would get, with just a headerback 70mm.

If so, does that stand for all years? Some models run a lot richer that others leading to a bit of a chaos on most forums.

Would be interesting to see some A/F numbers if you have them.

Dont get me wrong, i am not trying to be an @rse here just trying to understand things a bit better.

Kostas.

s2konroids

Probably the jist of it Kostas, a standalone needs more features as well...its a standalone .

Sorry long post here sorry . I've spent too much time on the dyno not with my car but with other peoples and helping my mate who tunes car's for a living.

Here's the ECU's i tried/tuned always with the same dyno:

All were with bolt's on's including a megan manifold.

Stock ECU
Spoon ECU
J's ECU
DTA standalone in a kitcar running an f20c.
GEMU running a supercharger.

The J's ECU actually performed better than the spoon overall on my set-up, but overall the VAFC2 performed the best, why? because its mapped to MY car and MY mods - its a simple as that with these ECU's, J's and spoon are mapped to their modifications, so its a little unfair.

IMO/IME anything more than a simple intake and decat and you definitely can take advantage of some-sort of tuning device, hell IIRC almost bone stock there's a little bit of gains to be had n/a - the evidence I've seen with this is flashpro on here. Flashpro (~£550 IIRC) is only available on MY06. Of course i agree with the guys regarding bang for buck.

Punchdrunk is right about leaning out. However you can add fuel but only a very small amount with a VAFC2, i had a hump of 13.3 AFR and managed to get it down to 13.2 before the stock ecu freaked out - not exactly a great result. With my bolt on's (manifold, decat, k&n, t1r v2 singlepipe) i was lucky as with MY setup it was 95% rich throughout the rev range prior to using the VAFC2. The big problem with a VAFC2 is you tune via the map sensor, effectively altering the voltage so the stock ecu reduces/increases fuel dependent on what it sees. Unfortunately this inadvertently effects the ignition timing (not too good) when you lean out it advances timing as a by product, so the chances of knock are increased and not the best for wringing as much power as you can but also smoothing the power curve (adding timing doesn't always add power too much and power will drop off). A common misconception is the VAFC2 will be 'learnt' over in WOT - that statement couldn't be further from the truth as LTFT/STFT are not applied in open loop, so you tune for WOT only. Of course we can't alter the timing with a VAFC2.

Earlier models due run a little richer throughout, but mainly at the very top end (where you get gains). However i taper the AFR off at the top end but still lean it out for retaining a little safety/cooling. I've seen some of the yanks tunes running 13.1 AFR at 8200rpm all the way to redline yikes! .

EMU is definitely a great bang for buck ECU with a PnP harness 2nd hand they can be picked up for around ~£400. You can do everything you need to do with it, AFR, vtec engagement, timing, idling, running bigger injectors, adjustment based on temp, reduce timing based on shift points, clamp MAP sensor voltage, increase rev limit etc etc. In all honesty apart from riding the stock knock sensor i cant see a standalone adding much more power than one n/a wise. Cell wise/adjustment points its a little lacking but good enough. The GEMU is a pre-processing unit which directly controls the injectors etc. I did slate the GEMU in years gone by . I tuned my car myself with a GEMU, beforehand running a VAFC2, deep down i knew it wasn't the best solution even more so running an SC so the VAFC2 had to go.

I dont have my s2k gallery any-more otherwise i would post some dyno's produced by me over the years. Giles was great he really did get the full potential of the GEMU, IIRC he even got it to detect knock and flash the indicator if detected . I need to stop getting sucked into the ECU debates. My days of tinkering with my car(s) are numbered as its PITA sometimes.

Its funny as will x bhp really make a difference is it worth x amount? - thats up to people. I can sure as hell tell the difference boosted though .

davecullen23

i ran the spoon with de cat and buddy club pro spec before supercharging. i felt the difference. the change over to vtec was alot louder and pulled harder, didnt notice much before vtec though. defo worth the money as it can be sold after you have done with it. only end up costing a couple of hundered after selling.

punchdrunk

Yes I have proof, Nabu - dyno proof

I have a MY00 ecu which is meant to run the richest of the lot.

The i/h/60mm cat back and 70mm HFC started off lean then gradually richened up before another lean spike before VTEC. Then it was progressively richer to redline. Mase was able to remove up to 12 points of fuel between 8-9k rpms and made significant gains up top ~ 10whp on the dyno.

With the 70mm header back, the AFR was pretty much lean from the off. The most we were able to trim was 3 points at 8700 rpms. Everywhere else we needed to add fuel which the VAFC doesn't like too much. 1 point of fuel would see my car backfire on the overrun, so I had to zero all setting in the end as it was a PITA.

My optimum VTEC point was 5800rpms - stock was 5900 rpms, so there really wasn't much in it. In the end I sold the VAFC and went back to stock.

The main difference between the VAFC and the Spoon is the torque. My guess is the Ecu retards timing when the VAFC trims fuel. Retarding the timing makes the car sluggish at low revs but quite revy up top. You can feel the more agressive timing with the Spoon as the car is more accelerative from the off and pulls hard to redline.

I take what AJ says with a pinch of salt. He is a very competent mapper but we don't all have a mate with a dyno

I've mapped a car before - it's not difficult, but dyno time is expensive. If you don't have competent mappers in your part of the world a pnp ecu is your best bet. You'll get 70/80% of the gains of the tuneable ecu's without the headache or expense of finding a mapper and they tend to hold their value when it comes to resale.

Your cash, your choice

MB

Nabu

Very interesting posts from both Irvatron and Punchdrunk.

Its all pretty usefull as i am currently waiting on a harness for a VAFC2 i've purchased and i have to say it made things a little bit more clear about all this. Hope i will get back with my findings on the subject

Thanks lads,