cats? you dont need no stinkin cats!

 

generally, this kind of engine displacement mod, rarely is able to be felt. But, they always deliver on the HP /torque side of the equation. generally, the power will go up from the percentage of displacement gain, up to a point.

 

Unfortunately in the UK we have emissions tests I can't afford to fail
I'd love to leave them off and watch it spit flames

 

If it were JUST a displacement change yes
It is going from a factory stock 4.7 to a 5.0 GT4 spec blue printed race engine
Then it is getting light weight clutch, headers, 200 cell cats and twin throttle intake

 

Awesome. It would be great to have this available in the US.

 

just got a text from Mike

"Johnny is off to the dyno. I have removed the front bricks for dyno cos this exhaust spec replicates 4.7L GT4. A quick test drive and all I can say is... HOLY st! And I thought Rosie was a video game. Answer to the definitive V12 Vs V8 thread = Johnny 550 without any doubt!!
I'd say already he's as fast as a std v12v in this latest small step yet still a halfway house step. A scientific test in 4th gear still wants to spin the wheels all the way to 7600 rpm (cold and damp) yet you are still pushed back into the seat all the way up to the limiter @7600 and the motor now surges with anger to the redline - scary what he will do with the full kit!"

Not too bothered about this set of dyno numbers as a lot of the "breathing" mods aren't on.
I'm going to go and have a drive of him in his current state on Monday!

 

Great stuff. Cant wait to hear some figures before , during, and after

 

I see. then, it will be pretty exciting! Ive heard the 4.7 GT4 is about 450rwhp, so I imagine these mods might be pushing the beast to over 500rwhp. So, cant wait to see the results.

 

Bamford Rose have done the first set of dyno as a 5.0GT4 spec race engine.
Intake and exhaust are yet to be done!
Bamford Rose sent me the following;

Johnny 550 5.0L engine was installed and fired up recently, from first fire the engine both purred like a kitten under the bonnet, and roared with a devilish burble out the tailpipe.


After a run in cycle he went straight to dyno, whilst we didn't need a roller to confirm what seat of the pants suggested was a complete animal, the numbers are entertaining and a real success to all the BR team that built him and got the project to this stage.

Who would of thought such an innocent looking car was such a savage supercar.






here is the raw data from the dyno.




The dyno result here is power at wheels which is not corrected.
Ambient pressure, relative humidity and air temperature were all measured by our own more accurate kit for us to more accurately than dyno provider calculate a correction factor.

Because Johnny 550 is only displacement upgrade currently, and exhaust system booty is to follow next, and because the delta uplift from the exhaust system is fairly well defined already, a prediction of what Johnny 550 will unleash full fat minus twin throttle inlet manifold can be calculated too.

Because we fitted the old 4.3L / non Vantage S exhaust system for this comparison, we removed the primary bricks meaning that this specification is directly comparable to GT4 racing. We wanted this because quite a number of race teams are looking to run this engine in competition as well as road cars. This means the delta from the BR exhaust system is a little less than normal here because we have to take into account that a brick is already missing.








I can then take all these figures and plot like this compared to standard 4.7L.....







The uplift in power and torque from standard 4.7L (redline), to johnny 550 as he is now (blue line) feels mega to drive and is far more uplift in relative terms from factory 4.3L to Factory 4.7L, this is because of the CNC combustion chamber and increased diameter inlet and exhaust valves.

Looking at this graph explains why Johnny feels so insane on the road, so insane that he almost feels like a standard V12V, so i thought i would plot this.....





Already just with displacement change Johnny is equal to V12V up to 5000 rpm. i thought that due to lower weight of Johnny Vs V12V he might pip V12V at power to weight ratio. The standard power to weight ratio of Vantage S is 263.8 BHP per ton, V12V is 290. Johnny at this first performance step change is 303.6 BHP per ton and with exhaust booty will rise to approx 325BHP per ton. When he has the exhaust booty the torque curve from 1000 rpm to redline will exceed V12V up to approx 6000 rpm, and because Johnny will both redline higher than V12V and produce more power, is the reason johnny will take the power to weight ratio, torque and absolute power output crown.

Next update is on Monday when MikeyK will drive him, after that test it is confirmation that the BR exhaust system delivers the numbers predicted here.

Some more sticky tyres might not go a miss too....

 

Immense. Just immense. When do we get to see some video?

 

I'm down on Monday having a drive I'll take some then
Still a bit of a way to go - it needs the twin throttles, new intake manifolds, cermaic coated headers, sports cats, drive shafts and ASM3 oil cooler fitting yet

Externally it's not going to look any different (which I love!)

 

I'm still grinning
I had a good look at the graphs that Mike put up yesterday before going over today, I realised;

• The 4.7 does not work best when reved right out peak torque is 5.5k rpm so I should have bee changing up early
• As Johnny stands (no twin throttle, standard 4.3 headers & cats, stock clutch, stock wheels & tyres) he currently has more torque between 2.7 & 5k rpm than a V12 and his peak torque is only 15Nm lower
• Power is a little down on the V12 across the range at the moment
• Mikes projections for the completed project look a little lower than I expected

So I put off going down to test drive it until the weather was better, I was worried it was going to spin the wheels up at every opportunity

Adrian and Mike were raving about how Johnny drove, I was still concerned so got Adrian to come with me (not sure what he was going to do from the passenger seat )
No rain so first things first roof down!
Starting him up there is a much more pronounce "bark" and a lovely crackle from the exhaust with a bit of throttle
I set of a bit tentatively with full traction control on expecting to squirm all the way down the road on cold wet tyres.
Surprisingly he just gripped and off we went at no drama, reved it out to about 6k a few times with no issues.
I think Adrian got bored at this point and suggested I rev it ti the still stock redline.
We got some straight road and I floored it, the sound is immense! (I hope we can stay close to it with the other bits going on)
It pulls in a completely linear way right up to the red line and feels like it wants to carry on, strangely the gear changes from the paddles are quicker and smoother even with out the light weight clutch set up (possibly the better balanced engine)
Not once did the traction control light come on (though Adrian thinks it may have been pulling some throttle at the top)
So I got back and felt confident enough to take Bincenzo for a "spin" two grown men giggling like girls
So Bamford Rose have some more work to do before the project is complete but so far it has exceeded expectations and the next stage is going to make it mental.

When I got back we had a long chat about, ASM2 vs ASM3, dyno figures and tyres.
They are going to work out the differences between ASM2 vs ASM3 fitted to the V12VS, one main difference is ASM3 has an oil cooler and pump (as does ASM1) we want to reinstate and possible improve on this to keep the gearbox temperatures down.
As I said earlier I was a bit disappointed with the project figures, talking to Bamford Rose it looks like Aston have a history of over stating outputs Vantage S's are making 415-420 and V12 Vanquishes ~ 540 BHP. So Johnny should be very close the new V12VS and Vanquish outputs (which was a target I had mentally set)
We all expected the stock tyres to struggle, surprisingly they didn't!) but with the next set of mods it may well be the case.
Not sure what to do about that yet. I could go up a size on the current wheels or got to DBS, V12V wheels, I really don't want to increase the unsprung weight if I can. Lets see what happens with ALL the mods on and dryer roads

 

Quick video

http://www.flickr.com/photos/25369163@N08/11728933584/

 

What a great snarl to that exhaust note.

Out of curiousity would there be any potential power gains with dual throttle upgrade, intake manifold upgrade and ECU update only. A kind of light performance upgrade ?

 

Yep more so at the top end when it gives much higher air volumes
They will be offering it as a kit in the future