I have a 2012 V8 Vantage.
It has 2 cat's in the header pipes (one per side) and then 2 more right after that. the o2 sensors are only watching the first cat. the second is just additional cleanup.
I have the sport model but not the sport exhaust. Does anyone know when they started doing the exhaust with 4 catalytic converters?

 

cats in the header started 4.7L engine MY 10

easy identifier is EGR. Earlier downstream cats system had EGR, your system / cats in header has no EGR

 

Mike,

Any idea whether the MY09 system made any more power? I ask because the independent magazine tests seem to show MY09 cars hitting slightly higher speeds through the 1/4 mile run (just a 1 -2 mph) than later cars. Just car-to-car variation or might there be something to it in the exhausts?

 

the loss of power from primary cat moved upstream is levelled by new system having better primary pipe design. I would put any difference down to normal fluctuation of build spec tolerances.
4.7L S (not N420 or other 4.7L models) had more optimised cal, but also has 7 speed gearbox, so a direct back to back comparison of the effect of the better cal is not possible. This is why they will find it hard to give V8 a high power send off before it ceases production - with the current hardware S is pushed about as far it can be (in OEM world), should hardware change the development and re-type approval costs will expend more than revenue from sale of cars returns making it impractical. Although i hope they do something, V8 deserves a good send off, it has served them well and lineage will miss it.

 

agreed. V8 has served them well and deserves a good sendoff.

there are several companies tuning the ECU on the earlier 4.3L engines and claiming 50-60 HP gains.

I have not seen anyone doing any tuning on the 4.7 though. Is the margin for gain just that small?

 

yeah, i have seen some interesting gains quoted too. More power to those companies because we have to throw exhaust hardware, airbox mods and ecu remap to get the gains you quote. Note to self, must try harder for an easier life.

the exact same delta gain from optimised cal for 4.7l is possible, the same as 4.3L. Stands to reason this is true, the same safety limits applied to 4.3L cal are being eroded for 4.7L. There are some minor changes to spark on 4.7L cal to make the gain slightly less than increased spark on optimised 4.3L cal. Howerever, this is not really important because changes to spark is not what returns the significant increase. This is because both engines have knock control and spark angle is already pretty much advanced across the curve to deliver the pre set knock over pressure limit.

for 4.3L, there isn't too much improvement to be had over factory power upgrade calibration. For 4.7L the very same can be done (take std cal and give it improvements the factory power upgrade cal has). Bamford Rose offers ECU remap for both 4.3L and 4.7L, which in terms of absolute spark angle, fuelling value, cam timing and throttle position is as optimised as it can be (the throttle wont open further than 90 degrees, for fuelling gas temp is as hot as you would dare, for spark knock control reports events and for cam timing any more advance returns no further airflow). But for what we offer, an ECU remap is more an enabler of the night and day transformations we create, instead of ECU remap being stand alone product.

 

Mike, I don't know why you bother with all that extra intake and exhaust work when you could just tweak the ecu

 

 

I have a bridge I would like to sell.

 

What's the best bang-for-buck then for my Vantage S? Should I replace the secondary cats with a straight pipe and do an ECU re-map? Will that be way too loud?

 

Get the Eurocharged tune for your ECU, that's the best bang per buck. Second is the second cats. On your vantage S if you don't want the car to be loud you can just get a set of 100-200 cell cats to quiet thugs down a bit but still give you most of the gains.

 

A good mod but not quite the best bang for buck if you think more deeply about it, because retaining the primary cat will always limit maximum potential power, and restrict how far an ECU remap can be optimised. Don't forget, a factory cal is only really compromised away from optimum for the sake of catalysts.

For Vantage S only because of better primary pipe design, remove headers and lovingly extract primary cat brick. Fit 200 cell secondary cats, 3 way exhaust valve control switch (loud / quite / switching as per factory set points) and with decent ECU cal to optimise spark and fuel and keep happy all monitoring systems upset by primary cat deletion, there you have a circa 45BHP upgrade for relatively, peanuts!

If you like this idea but don't want to attack your existing Vantage S headers, i have a pair with cats already removed that could bolt straight on, and with ECU remap and hardware for exhaust switch, would be ready to fit and enjoy kit without too much hassle

 

Mike: I just sent you a PM... but curious if this will affect the emission light as the sensors sits just aft of those primary cats, not down-stream.

 

Exhaust and tune is pretty much the standard starting point for modifying most cars (some can get a lot of power from an intake, too). The concept of swapping out the OEM cats for high-flow cats or even going cat-less is pretty simple - imagine the cat is a pillow, and then have that pillow on your face and try to breathe through it. An OEM cat is a very dense pillow that's very difficult to breathe through. A high-flow cat is less dense and allows you to breathe that much more easily though it. Going catless is like breathing through just the pillow case.

The tune just makes sure the computer is happy since the OEM programming expects the OEM cat to be there. Some cars are more sensitive than others to these things. Even doing just the exhaust and skipping the tune, your car will be fine (but you'll likely have a CEL for it), but of course the tune is highly recommended.

 

Thanks, i will reply PM shortly.

The Bamford Rose ECU remap / upgrade is cel / error state free. Its curious as to the reasons why, but recently i have indeed seen (not BR) cars with modified cats and despite a remap, yet still trigger a cel. Clearly not everybody can write to all parameters of ECU, and whilst a mod in the manner i suggest is a winner for everyone, the electronics is a hurdle for some to deliver that hardware solution.