Any benefit fitting an exhaust manifold without an ECU?
09-09-2012, 12:42 PM
#1
Registered User
Thread Starter
Any benefit fitting an exhaust manifold without an ECU?
I'm tempted by a nice tubular manifold to replace the gash looking lump of OE pig iron hanging from my engine. The question is, will I see any noticeable benefit without also getting an ECU and tuning work done?
I have an HKS cat back and K&N Gen ii kit, am I in danger of it running lean as a result?
I dont really want the expense of an AEM etc, would I need a VAFC or something similar or will the OE ECU cope?
(I really shouldn't have gone peering into other peoples engine bays at JAE, it makes me feel inadequate)
I have an HKS cat back and K&N Gen ii kit, am I in danger of it running lean as a result?
I dont really want the expense of an AEM etc, would I need a VAFC or something similar or will the OE ECU cope?
(I really shouldn't have gone peering into other peoples engine bays at JAE, it makes me feel inadequate)
09-09-2012, 12:59 PM
#2
I've said this many times but since its you 
Its hard to say by what extent but it will lean it out more around vtec but the cam switch over is just for a split second it would probably hit high 13's/low 14's not a major problem for that short period of time, up top it will gain a small amount more because the stock ECU runs rich up top. My advise would be to go on a dyno. A rough guide of suitable AFR regions are 12.7 to 13.2 range, the S sweet spot is around the 13.2 range.
In a nutshell it wont make much difference as an ECU is required to 'make the most out of modifications', you are running a hard coded map for the car standard, a manifold and intake may yield (*roughly*) 6BHP tops without an ECU.
Having tuned about 6 S2000's and on my 7th now, i have quite a bit of experience (flashpro, AEM S1/S2, DTA, VAFC2 and Greddy emanage ultimate) - the last 3 i tuned had some areas where they needed the mixture richened out and the VAFC2 did well, you've really got to take in account tacho inaccuracy and make the most out of the adjustment points and have a mental note of what the stock ECU is doing.
A VAFC2 is a good bang for buck, since you lean the mixture out and can richen it up by a small amount (but only a small amount as the VAFC2 isnt that good at adding much fuel). When you lean out you inadvertently add ignition timing and vice versa but you want to this to an extent anyways, however you dont want to lean it out and add ignition timing everywhere and you want varying levels of advance, there are places where you actually want to lean out but remove timing, or simply richen out - the VAFC2 can't do all of this.
In summary, richen mixture it retards timing, lean out mixture add timing this is because it is MAP sensor based tuning as opposed to injector duty cycle control - this is all you can do. You can also alter the vtec point, very beneficial especially when running a decat and the stock point is not optimum.
If you dont want to spend a lot of money a GEMU is a better investment, a VAFC2 is simpler, cheaper and good but not brilliant. If i didn't want to spend a lot of money for the cost of £100 or so second hand for a VAFC2 its a no brainer - i think Simons2000 is selling one in the FS section?
This gives you an idea of things https://www.s2ki.com/s2000/topic/955...#entry21738058
With the above said a good piggyback and standalone vary in complexity and fine adjustment so each step yeilds more power and smoothness, the standalone being the best/ultimate and is better than a VAFC2.
HTH
Its hard to say by what extent but it will lean it out more around vtec but the cam switch over is just for a split second it would probably hit high 13's/low 14's not a major problem for that short period of time, up top it will gain a small amount more because the stock ECU runs rich up top. My advise would be to go on a dyno. A rough guide of suitable AFR regions are 12.7 to 13.2 range, the S sweet spot is around the 13.2 range.
In a nutshell it wont make much difference as an ECU is required to 'make the most out of modifications', you are running a hard coded map for the car standard, a manifold and intake may yield (*roughly*) 6BHP tops without an ECU.
Having tuned about 6 S2000's and on my 7th now, i have quite a bit of experience (flashpro, AEM S1/S2, DTA, VAFC2 and Greddy emanage ultimate) - the last 3 i tuned had some areas where they needed the mixture richened out and the VAFC2 did well, you've really got to take in account tacho inaccuracy and make the most out of the adjustment points and have a mental note of what the stock ECU is doing.
A VAFC2 is a good bang for buck, since you lean the mixture out and can richen it up by a small amount (but only a small amount as the VAFC2 isnt that good at adding much fuel). When you lean out you inadvertently add ignition timing and vice versa but you want to this to an extent anyways, however you dont want to lean it out and add ignition timing everywhere and you want varying levels of advance, there are places where you actually want to lean out but remove timing, or simply richen out - the VAFC2 can't do all of this.
In summary, richen mixture it retards timing, lean out mixture add timing this is because it is MAP sensor based tuning as opposed to injector duty cycle control - this is all you can do. You can also alter the vtec point, very beneficial especially when running a decat and the stock point is not optimum.
If you dont want to spend a lot of money a GEMU is a better investment, a VAFC2 is simpler, cheaper and good but not brilliant. If i didn't want to spend a lot of money for the cost of £100 or so second hand for a VAFC2 its a no brainer - i think Simons2000 is selling one in the FS section?
This gives you an idea of things https://www.s2ki.com/s2000/topic/955...#entry21738058
With the above said a good piggyback and standalone vary in complexity and fine adjustment so each step yeilds more power and smoothness, the standalone being the best/ultimate and is better than a VAFC2.
HTH
09-09-2012, 01:12 PM
#3
Registered User
Thread Starter
Ah thanks.
I've just realised the searching I was doing included the US forums so after reading 20 or so threads on it adding between a hundred and a million horsepower I decided to just ask.
Thank you.
I've just realised the searching I was doing included the US forums so after reading 20 or so threads on it adding between a hundred and a million horsepower I decided to just ask.
Thank you.
So you can see where I'm heading...
