equal & unequal length headers
#1
equal & unequal length headers
Has anyone had good or bad results using aftermarket equal or unequal headers on there scooby, the reason i ask is that I've been advised against a certain make of equal length headers (which i won't name) as they a power loss, so anyones views would be appreciated.
Cheers
Granby
Cheers
Granby
#2
There are around seven different sets of headers on the market, they all perform very similar in terms of power / torque gains.
In terms of equal or unequal length there arent any true equal length ones on the market and the main difference is that the ones which are nearly equal lose a bit of the scooby / boxer rumble, the unequal variety keep this noise.
IMHO the best type to go for in terms of performance / noise / quality and value for money are the Gruppe-S style un equal length.
To get the best out them you will need to remap which ever type you go for.
In terms of equal or unequal length there arent any true equal length ones on the market and the main difference is that the ones which are nearly equal lose a bit of the scooby / boxer rumble, the unequal variety keep this noise.
IMHO the best type to go for in terms of performance / noise / quality and value for money are the Gruppe-S style un equal length.
To get the best out them you will need to remap which ever type you go for.
#3
Thanks very much for the reply, just a couple of questions, do you think this is a worthwhile upgrade (MY04 WRX with decat uppipe - decat downpipe - Ninja backbox - remap by Bob Rawle) has been on a rolling road and got 269bhp / 300lbs and where can i get the Gruppe-S headers
Cheers
Granby
Cheers
Granby
#4
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mate all header did for me was extra torque - yeah i love them but so don't
i did it as I thought it was a nice way of doing away with the up pipe cat
you would have to get the car mapped again
think you would get more from injectors and turbo
i did it as I thought it was a nice way of doing away with the up pipe cat
you would have to get the car mapped again
think you would get more from injectors and turbo
#6
Its about the overall set-up not just the individual componants, injectors will only be neccessary when you start to flow more air into the engine via induction kits, new turbos etc and the current injectors cant flow any more. If you are wanting 350 ish on the WRX get yourself a VF35 and intercooler off an STi followed by a remap
#7
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Do you really need a remap for headers? Why is this? I can see the remap being needed for intake mods but surely the exhaust is just exiting quicker.
On some of my older cars there was a distinct scavanging effect from the manifold/headers. I am pressuming that a turbo would cause a sufficient restriction to negate this effect?
On some of my older cars there was a distinct scavanging effect from the manifold/headers. I am pressuming that a turbo would cause a sufficient restriction to negate this effect?
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#8
Any modifications that allow an engine to "breathe" better either on the inlet or the exhaust side needs accounting for in terms of fuel & ignition, just one example by fitting headers is that the headers will more than likely move the spool up point of the turbo so fueling & ignition will need setting up to account for this.
#9
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Conrad,
So the spool up will be earlier than before due to better gas flow? I'm assuming this to be the case.
Does the ECU map not allow for the turbo coming in earlier and deal with ignition and fueling. I would imagine that the boost level would determine the fuel needed and ignition advance more so than rpm.
Sorry if the ECU can fuel and deal with the ignition advance a one particular rpm why cant it do it at another, lower rpm.
I just dont get this mapping stuff.
I'm off to design one that suits every mod I have plus any future mod I might make, LOL!!. Yeah right, like its ever going to happen!!
So the spool up will be earlier than before due to better gas flow? I'm assuming this to be the case.
Does the ECU map not allow for the turbo coming in earlier and deal with ignition and fueling. I would imagine that the boost level would determine the fuel needed and ignition advance more so than rpm.
Sorry if the ECU can fuel and deal with the ignition advance a one particular rpm why cant it do it at another, lower rpm.
I just dont get this mapping stuff.
I'm off to design one that suits every mod I have plus any future mod I might make, LOL!!. Yeah right, like its ever going to happen!!
#10
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mate i agree, ive never remapped mine yet
your maf sensor measures how much air is coming in and all the other sensors measure everything else.
if the standerd map cant handle say x amount of boost at x rpm then i can see why you would need it remapped, but for mild tweaks the standerd stuff has sum variance hasnt it?
i mean no 2 engines are the same so it must have?
your maf sensor measures how much air is coming in and all the other sensors measure everything else.
if the standerd map cant handle say x amount of boost at x rpm then i can see why you would need it remapped, but for mild tweaks the standerd stuff has sum variance hasnt it?
i mean no 2 engines are the same so it must have?
#11
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I have HKS headers on mine, and full decat and although I haven't had it rolling roaded, It seriously flies compared to the STi4 I had with same mods minus the headers.... Not cheap though.
TEK3 on the way and off to PE rollers soon
MB
TEK3 on the way and off to PE rollers soon
MB
#13
Originally Posted by Welloilbeefhooked
Conrad,
So the spool up will be earlier than before due to better gas flow? I'm assuming this to be the case.
Does the ECU map not allow for the turbo coming in earlier and deal with ignition and fueling. I would imagine that the boost level would determine the fuel needed and ignition advance more so than rpm.
Sorry if the ECU can fuel and deal with the ignition advance a one particular rpm why cant it do it at another, lower rpm.
I just dont get this mapping stuff.
I'm off to design one that suits every mod I have plus any future mod I
might make, LOL!!. Yeah right, like its ever going to happen!!
So the spool up will be earlier than before due to better gas flow? I'm assuming this to be the case.
Does the ECU map not allow for the turbo coming in earlier and deal with ignition and fueling. I would imagine that the boost level would determine the fuel needed and ignition advance more so than rpm.
Sorry if the ECU can fuel and deal with the ignition advance a one particular rpm why cant it do it at another, lower rpm.
I just dont get this mapping stuff.
I'm off to design one that suits every mod I have plus any future mod I
might make, LOL!!. Yeah right, like its ever going to happen!!
Your turbo will actuall spool later, the larger diameter tubing will slow gas speed down at lower RPMs but the headers really kick in when RPM rises because they are able to flow so much more gas than before.
Your ECU has two ways of working Open Loop Control and Closed Loop Control. Without going too deep I'll try to explain.
Open Loop Control
Your ECU monitors boost presure, MAF, MAP,TP(Throttle Position) and RPM, based on all these parameters it then looks at the fuel and ignition tables (like excel) and puts the appropriate(fixed value in table, entered by OEM or mapper) fuel & ignition values out to the injectors, ignition drivers etc. You will note that these tables hold "fixed values" which were entered by the OEM or mapper who last did your ECU.
Closed Loop Control
Your ECU monitors boost presure, MAF, MAP,TP(Throttle Position) and RPM, based on all these parameters it then looks at the fuel and ignition tables (like excel) and puts the appropriate value in the table, (entered by OEM or mapper) fuel & ignition values out to the injectors, ignition drivers etc
*Closed Loop bit coming. It then checks the Lamda sensor to see if the mixture is the correct AFR, if it is not then the "ECU makes adjustments" to either fuel or ignition to achieve the desired result. Usually find the ECU in closed loop in steady state conditions like cruising not mad foot to the floor acceleration.
By remapping we are changing the "fixed" values in the fuel & ignition tables to achieve the correct AFR during open loop control.
When ever you make changes to the air going into an engine or the exhaust coming out of an engine these fixed values need amending
Hopefully that wasnt too complicated lol
#16
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headers?
hi m8,
i have roger clarke motorsport headers on my sti 8 ra, hooked up to a bob rawle full decat system, its still sounds good and goes like f**k!! though that may be more to do with mr simpsons magic fingers doing there stuff!!
cheers robin.
i have roger clarke motorsport headers on my sti 8 ra, hooked up to a bob rawle full decat system, its still sounds good and goes like f**k!! though that may be more to do with mr simpsons magic fingers doing there stuff!!
cheers robin.
#17
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Originally Posted by Conrad_Bradley
Your turbo will actuall spool later, the larger diameter tubing will slow gas speed down at lower RPMs but the headers really kick in when RPM rises because they are able to flow so much more gas than before.
Your ECU has two ways of working Open Loop Control and Closed Loop Control. Without going too deep I'll try to explain.
Open Loop Control
Your ECU monitors boost presure, MAF, MAP,TP(Throttle Position) and RPM, based on all these parameters it then looks at the fuel and ignition tables (like excel) and puts the appropriate(fixed value in table, entered by OEM or mapper) fuel & ignition values out to the injectors, ignition drivers etc. You will note that these tables hold "fixed values" which were entered by the OEM or mapper who last did your ECU.
Closed Loop Control
Your ECU monitors boost presure, MAF, MAP,TP(Throttle Position) and RPM, based on all these parameters it then looks at the fuel and ignition tables (like excel) and puts the appropriate value in the table, (entered by OEM or mapper) fuel & ignition values out to the injectors, ignition drivers etc
*Closed Loop bit coming. It then checks the Lamda sensor to see if the mixture is the correct AFR, if it is not then the "ECU makes adjustments" to either fuel or ignition to achieve the desired result. Usually find the ECU in closed loop in steady state conditions like cruising not mad foot to the floor acceleration.
By remapping we are changing the "fixed" values in the fuel & ignition tables to achieve the correct AFR during open loop control.
When ever you make changes to the air going into an engine or the exhaust coming out of an engine these fixed values need amending
Hopefully that wasnt too complicated lol
Your ECU has two ways of working Open Loop Control and Closed Loop Control. Without going too deep I'll try to explain.
Open Loop Control
Your ECU monitors boost presure, MAF, MAP,TP(Throttle Position) and RPM, based on all these parameters it then looks at the fuel and ignition tables (like excel) and puts the appropriate(fixed value in table, entered by OEM or mapper) fuel & ignition values out to the injectors, ignition drivers etc. You will note that these tables hold "fixed values" which were entered by the OEM or mapper who last did your ECU.
Closed Loop Control
Your ECU monitors boost presure, MAF, MAP,TP(Throttle Position) and RPM, based on all these parameters it then looks at the fuel and ignition tables (like excel) and puts the appropriate value in the table, (entered by OEM or mapper) fuel & ignition values out to the injectors, ignition drivers etc
*Closed Loop bit coming. It then checks the Lamda sensor to see if the mixture is the correct AFR, if it is not then the "ECU makes adjustments" to either fuel or ignition to achieve the desired result. Usually find the ECU in closed loop in steady state conditions like cruising not mad foot to the floor acceleration.
By remapping we are changing the "fixed" values in the fuel & ignition tables to achieve the correct AFR during open loop control.
When ever you make changes to the air going into an engine or the exhaust coming out of an engine these fixed values need amending
Hopefully that wasnt too complicated lol
I agree that a remap will provide gains in spool, if not using a dawes of MBC, but amending the fixed values is not needed. It will provide imporovents but the MAF is great at compensating for breathing mods.
Tony.
#18
Originally Posted by Welloilbeefhooked
Conrad,
So the spool up will be earlier than before due to better gas flow? I'm assuming this to be the case.
Does the ECU map not allow for the turbo coming in earlier and deal with ignition and fueling. I would imagine that the boost level would determine the fuel needed and ignition advance more so than rpm.
Sorry if the ECU can fuel and deal with the ignition advance a one particular rpm why cant it do it at another, lower rpm.
I just dont get this mapping stuff.
I'm off to design one that suits every mod I have plus any future mod I might make, LOL!!. Yeah right, like its ever going to happen!!
So the spool up will be earlier than before due to better gas flow? I'm assuming this to be the case.
Does the ECU map not allow for the turbo coming in earlier and deal with ignition and fueling. I would imagine that the boost level would determine the fuel needed and ignition advance more so than rpm.
Sorry if the ECU can fuel and deal with the ignition advance a one particular rpm why cant it do it at another, lower rpm.
I just dont get this mapping stuff.
I'm off to design one that suits every mod I have plus any future mod I might make, LOL!!. Yeah right, like its ever going to happen!!
The explanation was due to the above reply
Originally Posted by Tone Loc
It will provide imporovents but the MAF is great at compensating for breathing mods.
Tony.
Tony.
Anyway, back on topic - back to headers ->
Last edited by The Fixer; 17 November 2004 at 05:39 PM.
#19
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Still not sure where you're coming from. A remap is not needed.... while remapping the standard ecu i never got anyway near the MAF ceiling, even using the standard maps load figures. Increasing the boost from 0.9 to 1.3 bar, i was still not using the last few rows of the map (with a lot of breathing mods). For the above question i would have said yes the ecu will deal with the differences in breathing due to the MAF. However the standard map can be optimised to increase torque/power and safety (but this is also the case on a car without headers).
MAF are wounderful things
Tony.
MAF are wounderful things
Tony.
Last edited by Tone Loc; 17 November 2004 at 05:46 PM.
#20
Remember the standard map is there based on EURO emmisions and is therefor very very safe in terms of fuel, ignition & boost, bolting headers on and not doing the remap is not making full use of the headers. Surely its better to fit something and optimise the car to make the best of the parts fitted ?
Thats why most of the aftermarket ECU's and the higher powered cars have ditched them then? They are quite often the limiting factor
MAF are wonderful things?
Thats why most of the aftermarket ECU's and the higher powered cars have ditched them then? They are quite often the limiting factor
#21
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Originally Posted by Conrad_Bradley
Thats why most of the aftermarket ECU's and the higher powered cars have ditched them then? They are quite often the limiting factor
Tony.
Last edited by Tone Loc; 17 November 2004 at 05:58 PM.
#22
Originally Posted by Tone Loc
High powered cars like Andy F, Pavlo and Bob's Ecutek Sti5, 3 well proven high power cars . Don't seem to harm some very high power skylines either. What exactly would you say is the power ceiling on a MAF based car given it can be mapped to suit various MAFs then? What is the restriction your talking about.... diameter?
Tony.
Tony.
Alot depends on the ECU in use and its abillity to give a MAF meter a new scale.
The diameter of the inlet pipe doesnt come into play in terms of a restriction until you are way up above 600 ponies. The restriction is in the ECU and its abillity to re-scale the voltage from the sensor into a range of air flowed that can be used.
Andy is using APEXi power FC which I assume copes well upto 600 HP, Bobs car running ECUTEK is 450 ish in reality before the NF mix is added.
Skylines, yes you are correct but did you notice they run two MAFS even on one turbo so they can try and measure how much air is going on?
We are way off topic here lol Somebody mention headers.....
Edited to add, what MAF's are useful for is to allow manufacturers to produce very envoiro friendly, safe running, mass produced engines out of the crate that can run within the OEM design criteria.
Last edited by The Fixer; 17 November 2004 at 06:11 PM.
#23
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Can you name an ecu that you can't rescale the MAF on... i can't (including all OEM Impreza ECUs). So going by that you say the restriction is only above 600bhp... wouldn't complain about that (or agree with it either).
We are way off topic, but it was said that a remap is need to fit headers. I don't agree with that. A euro car will compensate via the MAF quite easily (and have an increse in torque and power), but as you say to get the most out of the car (headers or not) a remap is a good option.
A remap is most definately needed for a MAP based ecu tho!
Tony.
We are way off topic, but it was said that a remap is need to fit headers. I don't agree with that. A euro car will compensate via the MAF quite easily (and have an increse in torque and power), but as you say to get the most out of the car (headers or not) a remap is a good option.
A remap is most definately needed for a MAP based ecu tho!
Tony.
#24
Originally Posted by Tone Loc
Can you name an ecu that you can't rescale the MAF on... i can't (including all OEM Impreza ECUs). So going by that you say the restriction is only above 600bhp... wouldn't complain about that (or agree with it either).
We are way off topic, but it was said that a remap is need to fit headers. I don't agree with that. A euro car will compensate via the MAF quite easily (and have an increse in torque and power), but as you say to get the most out of the car (headers or not) a remap is a good option.
A remap is most definately needed for a MAP based ecu tho!
Tony.
We are way off topic, but it was said that a remap is need to fit headers. I don't agree with that. A euro car will compensate via the MAF quite easily (and have an increse in torque and power), but as you say to get the most out of the car (headers or not) a remap is a good option.
A remap is most definately needed for a MAP based ecu tho!
Tony.
As for the 600 HP restriction on inlet pipe diameter I am referring to Subaru's and the work APS did in Auz where they found it to be a restriction above 600hp which is why there new DR650 kits are rotated mount turbo so they can get a bigger inlet pipe (or one without the flattened 90 degree bend in it)to the turbo.
Yes the ECU will compensate for the headers but it wont make the best out them either which is why we both agree a remap will make the most of them MAF or MAP based ECU.
Sorted
#25
In actual fact the ecu won't compensate for anything, the values that are present in the open loop section don't change just because you fit headers and if they are not suitable for the load points then used cannot adjust or compensate in any way, only the closed loop section does that. So a map adjustment is needed. If discussing a maf with an 80mm barrell then it will more than cope up to mid 500's, the smaller new age gets pushed to the limit but a change to 80mm (as per my STi9) soon fixes that however a map change is necessary to rescale.
Equal length headers are not suitable for STi's as the cams don't work, non-equal length are best for sure, there are two/three manufacturers that make ad sell true equal length btw. Best for me has been those based on the Ion design but using proper flange couplings which overcome the gasket blow problems people have, these available from RCM. Primary and up pipe diameters are critical though.
And btw Conrad has no idea what power and torque I'm currently running off the oem ecu in the '5, it made just over 500 using Link or Motec, I'll publish some figures as and when. It will be six speed though.
And I always use Japanese grade fuel in my JDM cars and always will, Andy uses Scottymax iirc.
cheers
bob
Equal length headers are not suitable for STi's as the cams don't work, non-equal length are best for sure, there are two/three manufacturers that make ad sell true equal length btw. Best for me has been those based on the Ion design but using proper flange couplings which overcome the gasket blow problems people have, these available from RCM. Primary and up pipe diameters are critical though.
And btw Conrad has no idea what power and torque I'm currently running off the oem ecu in the '5, it made just over 500 using Link or Motec, I'll publish some figures as and when. It will be six speed though.
And I always use Japanese grade fuel in my JDM cars and always will, Andy uses Scottymax iirc.
cheers
bob
#26
Originally Posted by Bob Rawle
And btw Conrad has no idea what power and torque I'm currently running off the oem ecu in the '5, it made just over 500 using Link or Motec, I'll publish some figures as and when. It will be six speed though.
And I always use Japanese grade fuel in my JDM cars and always will, Andy uses Scottymax iirc.
cheers
bob
And I always use Japanese grade fuel in my JDM cars and always will, Andy uses Scottymax iirc.
cheers
bob
Bob, only guessing at 500 HP for your STi 5 based on figures banded about on here and 22B, feel free to correct me if its wrong. Your car was brought up by Tony on regard to MAF's nothing else.
#28
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Originally Posted by Conrad_Bradley
Thats why most of the aftermarket ECU's and the higher powered cars have ditched them then? They are quite often the limiting factor
MAF is far superior on a turbo car in my opinion. This is with regard to the self compensating nature and potential power output.
Andy