Advice on Induction & Exhaust components

Mik0

Member
Messages
30
Hello everyone,

I've purchased a DC5 ITR on Saturday. It's my first ever Honda, I've had Japanese cars previously but mainly Nissans and Mazdas, and I've always wanted one of these so decided to pick one up whilst they're still reasonable!

It's a 2001 C-Pack without the "Engine Start" button. It's showing 123k however it's a mixture and I believe the true figure is around 90-100k miles.

It's a standard K20A with a few breather mods and an exhaust. In terms of condition the cars pretty clean apart from a few brewing spots of rust on the rear arches which I will catch ASAP before it FUBARs itself.

The spec is roughly:

Toyosports Decat manifold
Mugen Intake
Tegiwa Hoses
Tegiwa Alu rad
Hard engine mounts

Suspension wise it's on BCs, it's mostly polybushed, and has Japspeed camber arms.

Wheels are Rota's with some PS3s and 4s. Standard Brembo's.

DC2 Recaros inside with red carpets.

The reason why I'm posting this into this section of the forum straight away is that I've been warned that running a de-cat mani with an aftermarket intake can potentially make it run too lean without being mapped, obviously having an adverse effect on the motor. Is this true, or is it an internet myth? As I've read arguments for and against I'm pretty confused still. I guess to fix this problem would be to get it mapped on a standalone ECU or a piggy back if something like that exists for Hondas? Otherwise, to actually have a cat again in the form of a new exhaust - and keep the mugen airbox?

Would picking up a cat, sticking on the standard mani and just getting a catback sort the issue?

Let me know what you guys think and recommend - please treat me as if I'm a complete alien when it comes to Hondas as that is the truth!

PS. I know the plates blurred out but its AT51 BXG, if anyone has any previous history or info on it that would be very welcome!

PS2 .. Here she is below!

IMG-7855.jpg
 

SamDC5

Advanced Member
Messages
1,433
Hello everyone,

I've purchased a DC5 ITR on Saturday. It's my first ever Honda, I've had Japanese cars previously but mainly Nissans and Mazdas, and I've always wanted one of these so decided to pick one up whilst they're still reasonable!

It's a 2001 C-Pack without the "Engine Start" button. It's showing 123k however it's a mixture and I believe the true figure is around 90-100k miles.

It's a standard K20A with a few breather mods and an exhaust. In terms of condition the cars pretty clean apart from a few brewing spots of rust on the rear arches which I will catch ASAP before it FUBARs itself.

The spec is roughly:

Toyosports Decat manifold
Mugen Intake
Tegiwa Hoses
Tegiwa Alu rad
Hard engine mounts

Suspension wise it's on BCs, it's mostly polybushed, and has Japspeed camber arms.

Wheels are Rota's with some PS3s and 4s. Standard Brembo's.

DC2 Recaros inside with red carpets.

The reason why I'm posting this into this section of the forum straight away is that I've been warned that running a de-cat mani with an aftermarket intake can potentially make it run too lean without being mapped, obviously having an adverse effect on the motor. Is this true, or is it an internet myth? As I've read arguments for and against I'm pretty confused still. I guess to fix this problem would be to get it mapped on a standalone ECU or a piggy back if something like that exists for Hondas? Otherwise, to actually have a cat again in the form of a new exhaust - and keep the mugen airbox?

Would picking up a cat, sticking on the standard mani and just getting a catback sort the issue?

Let me know what you guys think and recommend - please treat me as if I'm a complete alien when it comes to Hondas as that is the truth!

PS. I know the plates blurred out but its AT51 BXG, if anyone has any previous history or info on it that would be very welcome!

PS2 .. Here she is below!

View attachment 7648
The AFR's will be out 100%, it's one of those where no one knows the damage it's doing without having the AFR's checked properly.

I've always seen it as if you're going to the effort of removing the cat then you may as well get the most benefit and have the car mapped.

The difference in response mapped vs unmapped is quite a lot, most of the time the VTEC engagement is lowered allowing a more usable power band without having to completely ring out the revs.

I'd 100% recommend having the car mapped, if you're near Runcorn or not too far I'd highly recommend EFI Parts.

Sent from my SM-G975F using Tapatalk
 

James-T

Advanced Member
Messages
626
Definitely get it mapped as Sam said above. Would give the car a nice dollop of midrange torque and more power throughout. Really noticable.

The header/decat does lean out the OE map, but I've never heard of any K20 ever going pop from this combo - scaremongering IMO, but still not ideal.

Hondata K100/KPRO are the ECU chips people use, but now there is Hondavert KPRO which is cheaper and has much the same functionality as KPRO.
 

Mik0

Member
Messages
30
Nice one, thanks guys.

I'm from Nottsinghamshire area so Runcorn is not too bad of a distance however I'll have a look around the forum for mappers local to me.

I'll also look at different recommendations but so far I'm being told K100 is the way to go?

Kind of stuck whether just to pick up a standard manifold and cat for now as I'd ideally like to get the rust sorted first before I jump into mapping - then stick the other bits on once I'm ready to get it mapped.

Cheers
 

James-T

Advanced Member
Messages
626
K100 gives the same performance as the KPRO, the difference is the K100 you cannot plug a laptop into it yourself - it's tuner only. It is about £300 cheaper though.

Standard manifold/cat is going to cost you around £600 these days.
 

Mebz

Advanced Member
Messages
1,011
Personally I'd get it mapped.

If you go down the hondata route (k100/kpro), EFI is the place to go.

Haltech have also started offering an ecu option now as well I believe.

If you choose to get it mapped, pick your mapper first, ask them what they want to use.
 

Lemons

Advanced Member
Messages
372
It will probably be ok to map the car after you have fixed the rust as long as you don't give it death all the time, but you are right to be concerned. Do you know how long it has been running like this? A few more months might not make a difference.

The top half of the manifold seems to be available and fairly cheap on eBay but the bottom half with the cat might be the expensive part.

Does the seller still have the manifold and cat? I would try to get hold of one anyway, if you are keeping the car a while, as you never know what the future holds, especially with all this ICE hate and emission zone stuff. Also useful to have for MOT time.

Sounds like you have a few jobs ahead of you, most likely the reason someone sold the car, so make sure you are committed before you start.
 

Mik0

Member
Messages
30
So the Mugen intake has been on for years apparently. As I've managed to get hold of some photos of it from 2012 and it has it on then, of course assuming it hasn't been taken off and changed between then and now.

In terms of the manifold, I think it's only been on it for about half a year or so. The cars pretty much been stood for a few months. The lad sold it because he couldn't afford the insurance after a few points and sections (not in this car) so he kind of passed it on from the last owner who I'm told was a Honda technician and looked after it... (don't worry it's having a big service asap)

24Lemons, indeed! Nothing I wasn't prepared for getting a car like this though! Plus stuff like this I'd rather get done so I know it's done and dusted rather than rely on previous owners etc. dunno it just makes me feel more confident.

What's the going rate for a Mugen intake? (allover the place on FB marketplace and eBay) I'm tempted to sell that on to perhaps get one a bit cheaper! I've been told that they're just JDM points kind of thing, and that Tegiwa performs better? Or is it purely down to the map and what the cars being used for?

Thanks for your help so far guys.
 

James-T

Advanced Member
Messages
626
Good condition Mugen intake with the proper snorkel you're looking around £400. They get nice cold air, give good throttle response but are quiet and perhaps a bit tame for some. I have a Mugen intake fitted.

Tegiwa one is a copy of the GruppeM, makes good power, is very loud but can be susceptible to rattling/knocking.
 

Mik0

Member
Messages
30
James, cheers for the info. I'd much prefer something a bit less subtle, and with your description of the Tegiwa/GruppeM, and listening to videos with them in I think I'll probs go with one of them!

Would you say straight swapping my Mugen for a Tegiwa or a Gruppe M is a fair trade? Or a Tegiwa +a bit ofcash my way sound more realistic?

Cheers
 

James-T

Advanced Member
Messages
626
GruppeM are rare these days...

I'd say a used Tegiwa with all the bits would go for £250-£300 ish so I would expect some cash your way if swapping for the Mugen.
 

JustinEET

Advanced Member
Messages
108
If you are using a stock exhaust manifold and just running without catalytic converter. Most likely your AFR aren't in harms way.
The stock ECU could still make corrections for that. With stock intake manifold and stock exhaust manifold you are still getting about the same vacuum and airflow even with better breathing "past" these points.
 

Mik0

Member
Messages
30
GruppeM are rare these days...

I'd say a used Tegiwa with all the bits would go for £250-£300 ish so I would expect some cash your way if swapping for the Mugen.
Nice, cheers James. I’ll have a gander through the Facebook groups and post a thread on here soon with regards to it.


If you are using a stock exhaust manifold and just running without catalytic converter. Most likely your AFR aren't in harms way.
The stock ECU could still make corrections for that. With stock intake manifold and stock exhaust manifold you are still getting about the same vacuum and airflow even with better breathing "past" these points.
Okay, that helps mate! I think I’ve decided that I’ll just get the K100 and map it to suit the manifold and intake thats on it. I spoke to EFI yesterday about it and got a much clear picture of it all together with the answers from here.

If I get a 2nd hand K100’d ECU can that still be chucked into my car and overwritten with a new map? Or does it have to be a brand spanker?

Thanks again guys!
 

carl hammond

Advanced Member
Messages
3,737
Nice, cheers James. I’ll have a gander through the Facebook groups and post a thread on here soon with regards to it.




Okay, that helps mate! I think I’ve decided that I’ll just get the K100 and map it to suit the manifold and intake thats on it. I spoke to EFI yesterday about it and got a much clear picture of it all together with the answers from here.

If I get a 2nd hand K100’d ECU can that still be chucked into my car and overwritten with a new map? Or does it have to be a brand spanker?

Thanks again guys!
Yeah any mapper can just do a new map and going forward it can also be tweaked. The K100 is a reusable item that can be mapped to the cars mods and even mapped back to be used with oem bolt ons etc. The only diff with ECU's is the PFL does not have the oem immobiliser whereas the FL does

Also just my opinion, I would never swap out a Mugen intake for a Tegiwa one, mugen is a great intake and depending on your needs and wants from the car then you can make the right changes going forwards.

Gruppe M, J's Racing are both concealed box items to consider, or you can go the route I have and many do for an exposed intake which is great for noise and gains AEM Long arm or Injen Long Arm (both sit down in the bumper by the passenger wheel area) so they don't get any heatsoak and have great airflow to them.
 

Mik0

Member
Messages
30
Yeah any mapper can just do a new map and going forward it can also be tweaked. The K100 is a reusable item that can be mapped to the cars mods and even mapped back to be used with oem bolt ons etc. The only diff with ECU's is the PFL does not have the oem immobiliser whereas the FL does

Also just my opinion, I would never swap out a Mugen intake for a Tegiwa one, mugen is a great intake and depending on your needs and wants from the car then you can make the right changes going forwards.

Gruppe M, J's Racing are both concealed box items to consider, or you can go the route I have and many do for an exposed intake which is great for noise and gains AEM Long arm or Injen Long Arm (both sit down in the bumper by the passenger wheel area) so they don't get any heatsoak and have great airflow to them.
That's really helpful Carl, cheers.

The idea of an exposed intake sounds great to me - less heatsoak and better airflow will definitely make the car perform a tad better on a day to day basis, and I suppose it cleans the engine bay up a little bit. In terms of usage, the car is used every day, at least for the next couple of years or so until I buy a house with a bigger drive or garage once the mortgage fix runs out haha! I understand why people would have a DC5 as a second car however it's a car I've decided is great and reliable (when everything is dialled up right obviously) for use everyday and as long as the motor is kept in decent order there isn't an issue with mileage. I'm not really one to rag the life out of cars, and more enjoy weekend drives out into the Peaks and potentially a very occasional track day with this, so the mods, maps and changes I do to this will be reflected based on it being a day-to-day fun car basically.
 

carl hammond

Advanced Member
Messages
3,737
That's really helpful Carl, cheers.

The idea of an exposed intake sounds great to me - less heatsoak and better airflow will definitely make the car perform a tad better on a day to day basis, and I suppose it cleans the engine bay up a little bit. In terms of usage, the car is used every day, at least for the next couple of years or so until I buy a house with a bigger drive or garage once the mortgage fix runs out haha! I understand why people would have a DC5 as a second car however it's a car I've decided is great and reliable (when everything is dialled up right obviously) for use everyday and as long as the motor is kept in decent order there isn't an issue with mileage. I'm not really one to rag the life out of cars, and more enjoy weekend drives out into the Peaks and potentially a very occasional track day with this, so the mods, maps and changes I do to this will be reflected based on it being a day-to-day fun car basically.
The only reason some don't like intakes like mine are they worry about hydrolocking (where the induction can suck up water), but this does not happen now, they are designed to prevent this (clearly stated on their warranty etc) and you can also get a hydrocover also as a secondary protection which I have (although it's only a track car anyway)

They are very good daily cars, this is my only car, but maybe selling for a split between a track only and road car soon) but I would if I was you get the K100 in, map it to what's there, then as and when you need and feel changes are wanted for your own personal preference then do them and get a map tweak (much cheaper than the initial mapping).

On the road I drive sensibly and to the speed limits at all times, roads here are nasty and I have nothing to prove, I have the fun where it's best and safe too, on the tracks. If you want to see the intake (engine bay without it) look at the pics in my build thread mate, engine bay looks a bit bare, but it does allow additional access to things lol
 

Mik0

Member
Messages
30
@carl hammond I definitely must have a rummage through your build thread as it looks really good and informative!!!

I will get some better photos of the car and a much more updated speclist and will make a start on my build thread this weekend :)
 

Reggie91

Advanced Member
Messages
1,280
Just my 2 pence worth on the intake side.

I had the AEM long arm when I first bought the teg. Sounds good, but the engine bay just had a big hole which I didn't like. Then bought a teg m intake which looked amazing, sounded great for the first few months until I got black flagged for it on track. After that the noise got a bit embarrassing and the rattles and squeaks from the scuttle panel got annoying!

This led me to buy a mugen intake and OMG it was perfect. Slightly louder then stock, looks very tidy in the bay, excellent quality. No more rattles or black flags! :D

With a lot of the talk online I asked Chris at EFI Parts who mapped my car if he can do a vacuum test on the intake and he said there is no restrictions with the mugen Vs the ram intakes (teg m/ gruppe m) he has mapped with. So from a performance point of view it's just as good.
 

Mik0

Member
Messages
30
Just my 2 pence worth on the intake side.

I had the AEM long arm when I first bought the teg. Sounds good, but the engine bay just had a big hole which I didn't like. Then bought a teg m intake which looked amazing, sounded great for the first few months until I got black flagged for it on track. After that the noise got a bit embarrassing and the rattles and squeaks from the scuttle panel got annoying!

This led me to buy a mugen intake and OMG it was perfect. Slightly louder then stock, looks very tidy in the bay, excellent quality. No more rattles or black flags! :D

With a lot of the talk online I asked Chris at EFI Parts who mapped my car if he can do a vacuum test on the intake and he said there is no restrictions with the mugen Vs the ram intakes (teg m/ gruppe m) he has mapped with. So from a performance point of view it's just as good.
That's really helpful cheers man. I'll have a look into it all, speak to some mappers and probably decide properly what I want to do in the next few weeks. Kind of feel like keeping the Mugen just for the JDM points haha!
 

carl hammond

Advanced Member
Messages
3,737
Just my 2 pence worth on the intake side.

I had the AEM long arm when I first bought the teg. Sounds good, but the engine bay just had a big hole which I didn't like.
Agreed it does look bare lol. I kind of regret selling my mugen one as that looked better in the engine bay as it looks complete :)

However as my setups 100% track friendly I won’t be changing it unless the car goes and at that point I’ll refit the oem u less the buyer wants it as is :)
 
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