Jackaroo Restrictors Removed

Hi Nobby

Midas must be kidding, It took bugger all time, to do. The boys charge me $40 to undo, pull out, die grind it neatly, new gasket and put back together. Very little noise differnece but noticable acceleration. I will post the pic tomorrow. Depending on where you are Rob Bliss exhaust at Geebung as awesome, try them. Print out Bradley's thread and take that with you, might help. cheers Ad

Hi Again Nobby

Did you get a quote on extractors?? I was chaing the a little while ago and even went looking in the USA, but couldn't find any for the 3.5 V6. Got a quote on custom jobs, about $1100. Please let me know how you go.
thanks
Adam

G'day mate,
Your on a winner!! Yep noticalbe difference, the tyres don't seem to take up too much. Have to say I love the look of the Jack now with the big coopers on it. Thanks heaps for the advise. Speedo is a little out at 100km/h on the speedo, It is sitting on 106 according to the GPS. Place at mulgrave can fitt a box for $275 to correct that, but don't think i will. Cheers Mate Adam

Cheers Peter,

Low end power seems plentiful. I will ring up holden and try again, they put me onto the expensive box. Cog change seems alot easier.
thanks
Adam

Hi Signman

Yep, I will be interested too. I will go an find a play park on the weekend and put it through its paces and climb a few things.

cheers

Adam

Signy, mate torque wont be a big issue, the whole notion of back pressure is a fallacy , headers or extractors are designed to 'scavenge' the exhaust gasses out of the combustion chamber, if there was meant to be back pressure then they couldn't work. An engine is just a big air pump, it needs as little restriction in as out. The main thing you will notice is the different throttle response down low especially just as the throttle blade is cracked, the restriction tends to 'cushion' a lot of the response. So it may be a bit more jerky in low1 or 2 over slow rocks etc.

Torque response ? i was out the other night on the wet roads and came out of a corner and fed in a 'normal' amount of throttle as before in 2nd, and she stepped out nicely flared straight up to about 5 grand and it was drift city for as long as i wanted. not that i'm irresponsible or anything !!!!!

"I have heard about back pressure and torque, but I cannot see how putting a restriction on efficient exhaust removal improves an engines ability to work. " as above - spot on champ, the only good explanation i can come up with is to cushion the acceleration rate of the engine under light load, to slow the 'flaring' of the revs in low trac situations. Only a prob because the isuzu engine is so damn good !!

As Bruce Garland said a while back when i was talking to him about it, they stick those in there so grandmas can drive 'em, so true Bruce..

Check my previous post for better descriptions and locations..

BYW everyone, my mun borrowed the jack last weekend to visit the relos while she is in town, she put about 260 k on it from full and i did another hundred and fifty before throwing in some fuel, result 12.3L/100 (mums foot is obviously lighter than mine !!). Since then i have been moving house - towing trailer etc. fairly loaded up and she ripped up some decent hills in 5th with no real strain, even rounded up a semi with about 800kg in the trailer without strain in 4th , from 80 to 110 ks.
next top up - result 13.6L/100 So - fair to say i'm pretty happy.. Cheers all, Brad