Rolling road today

Simon

Simon

Simon

Caporegime
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Nothing that impressive compared to other members (Gibbo ;) )

But been on the Rollers today with the new cat back exhaust system (still need to fit the decat, be good to see the diff it makes on its own though)

S2000Power.jpg


Last run is dotted and was on Esso 97 + standard exhaust, this time BP ultimate ( so can't really compared before and after).

Old system was 23kg, new one 18kg so not the lightest of aftermarket systems but better than a smack in the face :p Some of the Ti single exits are only 5kg.
 
Guttless VTEC with no low down torque etc etc :D

Interesting how the exhaust has improved torque all the way through. So much for the "engines need back pressure" theorists...
 
Err, the 153lbft doesn't seem to tally with the graph and scale on the right. Is the scale in Nm, even though it says it's in lbft?
 
Dogbreath said:
So much for the "engines need back pressure" theorists...
Click to expand...

Is that not more people miss understanding the fact that if you get too wide an exaust the gasses slow down too much in the pipe and it starts to be detrimental.

Seems a good improvement, what exaust did you get?
 
I assume that if you have very little back pressure, the problem is that at low revs where the exhaust valves are open for a comparitively long time, you start to loose the unburnt fuel/air mix before the exhast valve closes?
 
not bad at all for just an exhaust change, wish my 2.0 lump would make gains like that, couldnt even dream of getting to 240bhp in the first place :eek:
 
Fine lower down, the 'off-vtec' cam will not cause any issues.

Exhaust isn't much different in pipe size just less restriction on the backboxs.
It's not just the exhaust change but also the change in fuel.

It's an Exhaustsuk/Cobra system. Only paid £200 second hand :D
 
Nice improvement and it was fun fitting it :p , just try getting a shorter FD to prove modding Honda's to go a lot faster doesnt have to cost the earth. :D

Did Martins DC5 turbo run?
 
Yeah his integra made 312hp. Just needs a bit more mapping.

Skyline GT-S with 2 more cylinders and a turbo only made 1.5hp more and a coupe turbo made 249.8hp so i got the 4th highest of the day.
 
penski said:
Not true.

The trick is to look at the torque curve - the more area 'under the curve', the better. :)

*n
Click to expand...
Depends on the gearing though. You need a large area under the graph, but only through a region you can keep it in by changing gears late. So if you can change up at 8k and end up back at 6k and that's where the power is then it'll just be a bit tedious to drive. Most people would expect that from a race engine, not a road engine though.
 
burns said:
Depends on the gearing though. You need a large area under the graph, but only through a region you can keep it in by changing gears late. So if you can change up at 8k and end up back at 6k and that's where the power is then it'll just be a bit tedious to drive. Most people would expect that from a race engine, not a road engine though.
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Every time people want to drive fast they will rev it to the redline regardless of what revs it is at.

Once you hit vtec in 1st gear you never drop below it on an S2000. Off vtec is still makes more torque than most 2.0 do peak anyway
 
Psycrow said:
Is that not more people miss understanding the fact that if you get too wide an exaust the gasses slow down too much in the pipe and it starts to be detrimental.
Click to expand...

Partly that, and partly because an engine tuned to operate with some exhaust back pressure will quite possibly lose power when the back pressure is reduced (with no other changes) due to resultant changes in fueling, though this is more noticeable with carburettored engines IME.
 
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