Just Cats
03-23-2004, 11:59 PM
#1
Registered User
Thread Starter
Join Date: Dec 2003
Location: Aus
Posts: 102
Likes: 0
Received 0 Likes
on
0 Posts
Just Cats
Fitted a pair of RT cats last night.
Besides suspension mods, my car is stock. I thought it would be interesting to first fit the cats and see the results before any other mods are done .
This should also give other owners an idea as to whether its a worth while mod.
No issues with fit they are made really well. A little smelly for the first couple of hours till they burn in a little.
There is definitely a noticeable gain in this mod. Accelaration has improved and it pulls alot harder after 4000rpm. Thats mostly where the gains seem to be.
No doubt in my mind its quicker than stock
I decided it was best to dyno and see if the A/F changes at all. You can see my stock results below. (5th gear)
This Friday I have another dyno booked to compare any changes.
Q. Is the A/F measurment from the exhaust accurate enough?
Besides suspension mods, my car is stock. I thought it would be interesting to first fit the cats and see the results before any other mods are done .
This should also give other owners an idea as to whether its a worth while mod.
No issues with fit they are made really well. A little smelly for the first couple of hours till they burn in a little.
There is definitely a noticeable gain in this mod. Accelaration has improved and it pulls alot harder after 4000rpm. Thats mostly where the gains seem to be.
No doubt in my mind its quicker than stock
I decided it was best to dyno and see if the A/F changes at all. You can see my stock results below. (5th gear)
This Friday I have another dyno booked to compare any changes.
Q. Is the A/F measurment from the exhaust accurate enough?
03-24-2004, 01:08 AM
#3
Nice work!
Do you have the raspy noise at WOT during some rpm levels?
And you have no other exhaust mods?
(I think these cats combined with Y-Pipe plus stock US muffler(theory) would make good gains for low cost with little noise. 8hp + 5hp + ~10hp = 23hp@wheels)
Cant wait for the dyno!
Do you have the raspy noise at WOT during some rpm levels?
And you have no other exhaust mods?
(I think these cats combined with Y-Pipe plus stock US muffler(theory) would make good gains for low cost with little noise. 8hp + 5hp + ~10hp = 23hp@wheels)
Cant wait for the dyno!
Last edited by mchapman; 03-24-2004 at 01:15 AM.
03-24-2004, 01:46 AM
#4
Registered User
Thread Starter
Join Date: Dec 2003
Location: Aus
Posts: 102
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by mchapman
Nice work!
Do you have the raspy noise at WOT during some rpm levels?
And you have no other exhaust mods?
Nice work!
Do you have the raspy noise at WOT during some rpm levels?
And you have no other exhaust mods?
No other exhaust mods at all.
The sound hasn't changed much, just a little deeper.
Trending Topics
03-25-2004, 11:36 PM
#11
Registered User
Join Date: Nov 2002
Location: Sydney Australia
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
I think the AFR is OK but I'd keep an eye on it if you plan any further mods. Your base AFR has more range than most I've seen anyway which may explain a lot of it. Mine is basically 12.5 throughout the entire range for example.
03-26-2004, 12:42 AM
#13
Registered User
Thread Starter
Join Date: Dec 2003
Location: Aus
Posts: 102
Likes: 0
Received 0 Likes
on
0 Posts
apsilon - I see your point about the A/F ratio after looking at the others in the dyno list you compiled.
They seem very linear compared to mine.
ypwpat - I'd say that yes your AFR would get a little leaner, but your gains would be more than just 6kw (in theory)
Raspy is kind of a light metalic rattle sound.
They seem very linear compared to mine.
ypwpat - I'd say that yes your AFR would get a little leaner, but your gains would be more than just 6kw (in theory)
Raspy is kind of a light metalic rattle sound.
03-26-2004, 02:11 AM
#14
Registered User
Join Date: Nov 2002
Location: Sydney Australia
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by Flasher
apsilon - I see your point about the A/F ratio after looking at the others in the dyno list you compiled.
They seem very linear compared to mine.
apsilon - I see your point about the A/F ratio after looking at the others in the dyno list you compiled.
They seem very linear compared to mine.
Did you reset the ECU after fitting the cats? How many km on them so far?
03-26-2004, 02:58 AM
#15
Registered User
Thread Starter
Join Date: Dec 2003
Location: Aus
Posts: 102
Likes: 0
Received 0 Likes
on
0 Posts
I've never reset my ECU. Often wondered if there is a benefit at all.
Only clocked up around 200 km so far with the cats.
I'm not an expert on the subject of AFR so all opinions are welcome.
Thats pretty much why I dyno'd before and after.
Has anyone found a change in AFR after fitting a cat back system like HiTech or the Amuse ? (next mod)
Only clocked up around 200 km so far with the cats.
I'm not an expert on the subject of AFR so all opinions are welcome.
Thats pretty much why I dyno'd before and after.
Has anyone found a change in AFR after fitting a cat back system like HiTech or the Amuse ? (next mod)
Last edited by Flasher; 03-26-2004 at 03:06 AM.
03-26-2004, 03:33 AM
#17
Registered User
iTrader: (2)
Join Date: Jan 2003
Location: Australia
Posts: 1,647
Likes: 0
Received 0 Likes
on
0 Posts
yeah... with the s-afcII, you can be able to balance the AFR. i once spoke to Peter about that and he said that's workable too. I think I will go for the s-afcII if I have the cats installed.
btw, thank you for all the info, that is really helpful to me in the near future!
cheers,
richie
btw, thank you for all the info, that is really helpful to me in the near future!
cheers,
richie
03-26-2004, 11:53 AM
#18
Registered User
Join Date: Nov 2002
Location: Sydney Australia
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by Flasher
Has anyone found a change in AFR after fitting a cat back system like HiTech or the Amuse ? (next mod)
Has anyone found a change in AFR after fitting a cat back system like HiTech or the Amuse ? (next mod)
I should be dynoing next weekend and will check the AFR again. Nothing has changed on my car since the last dyno except about another 5000km and the US duct which should be insignificant. Should also have an answer as to why the results have changed at Croydon.
03-26-2004, 05:31 PM
#20
Registered User
Join Date: Nov 2002
Location: Sydney Australia
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
Someone correct me if I get this wrong. I tend to get AFRs backwards sometimes.
It really varies depending on rpm and load (and probably between types of engines). At idle 14.7 is generally considered to be around ideal but you don't want that at peak revs. You'd like it to come down to about 12.5 under WOT.
Flashers' graph is interesting because it starts out so lean and becomes overly rich compared to the other 350Z charts I've looked at (not that I've looked at that many). If you look at my AFR chart for example it starts off about 13 and comes down to about 12 which is a fairly flat chart.
It really varies depending on rpm and load (and probably between types of engines). At idle 14.7 is generally considered to be around ideal but you don't want that at peak revs. You'd like it to come down to about 12.5 under WOT.
Flashers' graph is interesting because it starts out so lean and becomes overly rich compared to the other 350Z charts I've looked at (not that I've looked at that many). If you look at my AFR chart for example it starts off about 13 and comes down to about 12 which is a fairly flat chart.