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M-B did 3 valves per cylinder. I wonder how that stacks up?
With two spark plugs per cylinder, it's almost as good as the four-valve cylinder heads, especially for big bore cylinders. The two plugs can burn a big bore as fast as a a single plug can burn a small bore. The single round exhaust port has the least possible amount of surface area, which reduces heat losses. Reduced heat losses are great for turbocharging and for lighting up the cats. For all of these reasons, the three-valve head is a serious competitor to the four-valve pent roof head.
Your totally right Greg, the Porsche's engineers did their engine math pretty well & like you say, it's a question of equation. I think the track & race guys comments (atb and John V.) are right on the button; it all depends on what you intend to do with your Tonka...If you start playing with the variables you'll add up to a new equation.
I don't know if you meaned WHP ou just HP, but to put an xtra 10 whp by just adding a new exhaust seems pretty darn good...the 30+ horses advertised by some (for an approximate 3k mod) seems to good to be true...
And having 'web dream' is not that unpleasant!!!
"Claims" are worthless. Dyno results can also be "optimized" (as we've seen many times) and can be also worthless.
While my hand fabricated, stainless, tig welded headers with my complete stainless exhaust system is a bit "pricey" (~$6,000) for the 928 crowd (but a bargain in almost any other crowd), it's nice to know that it really works.....and sounds fantastic (*)
Money back guarantee that if the car is properly tuned, has a viable engine, and has injection components up to specification, that the customer will see a 30 rwhp increase. (S4's will require an injector change to get 30 more horsepower.)
(*) "fantastic" is a relative term. My system makes the car a bit more throaty in normal operation, but is very quiet around town. This allows long freeway drives without the associated "brain" damage" from exhaust being too loud or having resonantion. However, when the gas pedal is floored, the system barks like a real hot rod. Many people claim my complete exhaust system to be the best V8 sound ever, with the perfect mixture of both quiet and "bark".
"Claims" are worthless. Dyno results can also be "optimized" (as we've seen many times) and can be also worthless.
While my hand fabricated, stainless, tig welded headers with my complete stainless exhaust system is a bit "pricey" (~$6,000) for the 928 crowd (but a bargain in almost any other crowd), it's nice to know that it really works.....and sounds fantastic (*)Money back guarantee that if the car is properly tuned, has a viable engine, and has injection components up to specification, that the customer will see a 30 rwhp increase. (S4's will require an injector change to get 30 more horsepower.)
(*) "fantastic" is a relative term. My system makes the car a bit more throaty in normal operation, but is very quiet around town. This allows long freeway drives without the associated "brain" damage" from exhaust being too loud or having resonantion. However, when the gas pedal is floored, the system barks like a real hot rod. Many people claim my complete exhaust system to be the best V8 sound ever, with the perfect mixture of both quiet and "bark".
Would you mind 'sharing' a sample of the 928 'eight symphony' with us?
Thank's Rob for the beautiful melodies, but I'm not quite shure the first two ones were 'stock' GTS sounds...seems like there's a SC or TC symphonic sound hidden somewhere?!! The last one seem's more like it's a 16v engine
You are not exaggerating at all! (Not that I've driven a lot of other 928's)...
Every time I get a chance to drive it, at least one random person stops and asks about the exhaust and the car...Again, my sincere thanks for everything...
For those on the board, I haven't posted yet about the car, the headers/exhaust, Greg's other modifications, Sean's new wiring harnesses, etc...unfortunate and unexpected work/family/life curve ***** had me sidetracked...
Anyway...the bottom line...the art and genius of the design of headers/exhaust totally transformed the car...In addition, Greg designed fuel injector adapters (now sold as a kit) that allows the use of new 24 lb. 4 hole injectors...And coupled with swapping the ECU for a US 85/86, and a thorough Sharktune...If I recall correctly, Greg mods added at least 35 rwhp to the dyno results...
Personally, I think the significance of his fuel injector adapter invention has been extremely overlooked here...With the euro injectors NLA, the only choice was to cross fingers and hope all the old ones could be successfully serviced by Witch Hunter...no other options...until now...
Anyway, lots more to follow in a separate post...but again, I am extremely grateful the help I have received from Greg, Sean, and Roger.
Respectfully,
Rich
Last edited by V33; 11-14-2015 at 02:55 AM.
Reason: spelling