354 bhp on the RR today
Discussion
Yo Griff guys,
Thought you guys might be interested, engine was rebuilt by Rob Robertson at V8 Dev,yet to be remapped after running in, but have posted the graphs....
Cheers fellas,
R.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Thought you guys might be interested, engine was rebuilt by Rob Robertson at V8 Dev,yet to be remapped after running in, but have posted the graphs....
Cheers fellas,
R.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Edited by Chilliman on Tuesday 4th October 18:33
It would be interesting to know the engine build spec and what induction you are using. My Rob built engine produces near identical numbers and interestingly the RR showed near identical transmission loss. Your peak torque however is at slightly higher RPM than mine which tops out at 4590. Is it an H404 cam or something slightly hotter ?
steve-V8s said:
It would be interesting to know the engine build spec and what induction you are using. My Rob built engine produces near identical numbers and interestingly the RR showed near identical transmission loss. Your peak torque however is at slightly higher RPM than mine which tops out at 4590. Is it an H404 cam or something slightly hotter ?
Steve, build spec is on my profile, cam is bespoke for the engine... I'm getting the cam spec from Rob, so can pass it on to you if you're interested, although originally Rob did say it was 'somewhere between a stealth and a 404'... I've named it the 'Naga' as naga chillies (as you may know) are very hot, and I've had some success growing them 
TVR Beaver said:
T.O.P. result... Well done that man... does it drive nice also?... 
Hi John, It's not wonderful at low revs in town, but we might be able to sort that with the remap. To be honest though I'm not too fussed, It's not particularly bad, I try not to do towns anyway, and the driving experience on the open road more than makes up for any bad town manners. You need to have a drive of it 
That's some serious torque... Is it all down to the extra half litre capacity ?Chilliman said:
Hi John, It's not wonderful at low revs in town, but we might be able to sort that with the remap. To be honest though I'm not too fussed, It's not particularly bad, I try not to do towns anyway, and the driving experience on the open road more than makes up for any bad town manners. You need to have a drive of it
Indeed.. would love to... and hope you can sort the low down manners.. with your ECU etc you stand a good chance I think.. as it can become annoying once you've become acustomed to the increase in BHP... May be they can tune a bit more torque in for you also so you get a full range improvement.. I guess at the moment you get a mad rush around the 3.5K mark so would be good to compliment this with something lower down... But I'm sure this is down to spark curve or something simple... (would have thought with the reduced stroke youd get torque?),... Looking great anyway... 
TVR Beaver said:
..would have thought with the reduced stroke youd get torque?..
???? - just have to work harder to get high compression at the end of the day. High comp giving extra gas pressure against the piston & rod to hold them together / cushion the blow always seems the best trade off to me ~ just as Rob notes that his 'big' stroked engines all rev fine....topsparks said:
Nice one,heres the graph for the 5.5 Rob built for me same induction as yours 404 mechanical with group A rockers.
Not wishing to sound negative - but is something amiss with the rpm scale on that graph..?Peak torque on the graph above is at a lower RPM than my TVR885 cam, which is lower RPM than the Stealth cam's peak torque RPM - the 404 cam (as I understand it) should be running peak torque at higher RPM still, hence the need for mechanical tappets etc...
Why does the torque peak so early on this graph - seems inconsistent with what I understand of the 404 cam's characteristics..?
Dom
It did pull like a train,when Rob first drove it after installing his engine he called me to ask"if there was anything wrong with my tyres" as he couldn't belive how much the wheels were spinning! Engine revved very freely,after a particularly spectacular exit from the Ace one evening it hit 7500 rpm!,as Dave Walker pointed out to me on a mapping session when he was looking at the ECU's history.
I'm not surprised - it's awesome torque 
I was just expecting the torque hump to be further up the rev-range with a 404 cam - and the BHP output thereby to be nearer to the torque value...
Thought maybe the flow was being limited by the heads, or perhaps you had changed the timing of the cam..?
Was just not the torque curve characteristics I was expecting to see from a 404, thats all...
Dom
I was just expecting the torque hump to be further up the rev-range with a 404 cam - and the BHP output thereby to be nearer to the torque value...
Thought maybe the flow was being limited by the heads, or perhaps you had changed the timing of the cam..?
Was just not the torque curve characteristics I was expecting to see from a 404, thats all...
Dom
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