FW: Exhaust - First Impression

From: John
Sent: Saturday, 6 October 2012 12:56 AM
To: JtC
Subject: Exhaust - First Impression

Phil said that the original design was really weird and not good. One side of the Y was a 2.5” pipe and the other a 2” pipe? With a 2” exit from the Y and 2” muffler/system.

New system is single, 2.5” throughout. There are no flanges and Phil will simply cut the engine pipes and fab new ones to suit when it is extractor time. No turn-down on the tip, but that can be changed when the extractors are done. Muffler is made by Redback; straight-through design. He won’t use anything else as Lukey/Walker are rubbish now and the Redback is much heavier construction.

The note is AMAZING! It sounds like a bigger V8 now and more like a muscle car, but not too much… still suits the limo that it is. Like before, but bigger and more “defined”. A healthy burble that can be heard from inside the car with the windows down. Come off the accel at speed and there is the beginning of a crackle (without it crackling – if you know what I mean). Inside the garage at idle, the sound is a deep burble. Once or twice I wondered if there was a drone/resonance at a certain rev level… will be interesting to see what you think.

What surprised me was the throttle response. I was expecting the change to come more with revs, but I noticed the extra torque the instant you touched the throttle from standstill. The bonnet lifts that little bit more and you are shoved back right off the mark. It reminds me of the change when the HR went from 1-barrel Stromberg to twin barrel. Accel-wise it feels like it is 200 kg lighter. It climbed out of Ourimbah, Mooney Mooney creek and Hawksbury River in the far right lane.

Phil also mentioned that he feels it should run cooler as the exhaust gasses aren’t as stuffed-up. I gave him a quick rundown of the past issues of overheating and said I would watch the temp light. It was a hot day and I was stuck in traffic on the short stretch between New England Hwy and start of F3… no overheating.

Phil was impressed with the new bushes throughout and said it was a tidy car with strong engine. I mentioned that a couple of cylinders were down on comp. He said short motors/heads were cheap.

Car is dusty from workshop, so needs a clean. Phil said it got a lot of interest from mates/visitors and they asked if it was his. He left it on the rear hoist to keep people away from it.

They are my initial thoughts; come up anytime tomorrow to check it out and get tools or bring the UC and we can look at it.

J