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Started by motec6.9, 14 October 2012, 06:48 PM

motec6.9

Hi guys this article explians it better than i ever could i used to fit exhaust but this is really helpfull information http://www.popularhotrodding.com/enginemasters/articles/hardcore/0505em_exh/ . Geoff  :)
Euro 6.9 255.6hp at the wheels. Watch this space.

gf

That was an interesting read! Some guy that builds exhausts was telling me horsepower for the money its far cheaper and safer to upspec a car exhaust than fiddle with a stock engine nearly every time. anyone reckon you really could get another 40hp out of a 116 with exhaust tuning?

motec6.9

Hi GF         this should help a 6.9 fitted with duel 2.5 inch exhaust will make about 190hp at the rear wheels . My car has extractors and Motec efi it made 215hp at the rear wheels before changing to larger throttlebody timming chain was done at the same time power then went to 293hp at the rear wheels. Confirming that throttlebody was the limiter. So at least with a 6.9 standard power is anywhere from 160 to 175hp at the rear wheels 2.5 inch duel exhaust lifts that to 190 so anywhere between 15 to 30 hp at the rear wheel. With extractors add another 15 to 20hp so yes it is possible but more likely about a 25 to 30 hp increase on a 4.5litre . I hope this helps . Geoff :)
Euro 6.9 255.6hp at the wheels. Watch this space.

motec6.9

Hi MT credit goes to Cam of 450SE 6.9 fame for pointing me in the right dirrection . He told me he had fitted a 560 throttle body to his M-100 and the car went much harder than before. I asked him to measure the difference in size it was 450 6.9 throttlebody 75mm same size a V6 Commodore. 560 throttlebody 81mm so i bought a 100mm aftermarket LS throttlebody and had manifold modified to fit new throttlebody. It also allowed me to run a proper TPS for the EFI not makeshift one fitted to K-Jet throttlebody. At this time it was also realised that timming marks were out so new timming chain was bought and fitted before retunning on dyno.As to what part of the 78hp increase belongs to the throttlebody TPS or timming chain i dont know. Unfortunately my car has been stagnant for a while as i now have 3 girls under the age of 3 . But the car will be completed and it is not for sale. Geoff :)
Euro 6.9 255.6hp at the wheels. Watch this space.

motec6.9

Hi MT it does need some mods but is doable. You can check with Cam to see if he still has his he tried to sell it to me a while back . Geoff :)
Euro 6.9 255.6hp at the wheels. Watch this space.

motec6.9

As for my extractors when i get around to painting the car i will ask if anybody wants copys made . Geoff :)
Euro 6.9 255.6hp at the wheels. Watch this space.

oversize

I'll need at least four sets!!!  LOL!   ;)  Motec your system is truly a work of art and the fabricators should get a good wrap for it!!!  Apparently the length of the secondaries has far more benefit than the length of the primaries.  I'd heard that it's almost impossible to silence an engine with performance cams, but maybe it's just a case of fitting more than one with the correct flow rate?
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

motec6.9

Hi Mark i have said it before this car sounds like a Broadside from the Bismarck ITS LOUD . But OMG it sounds good TJ heard it 1 day in my driveway when my father inlaw was moving it while i was away with work. Geoff ;D
Euro 6.9 255.6hp at the wheels. Watch this space.

ZCarFan

On my Impala, I quieted it down by employing a crossover about 1/3 of the way down the exhaust.  This makes a fairly big difference in both volume and tone (smoother and quieter).  I also included glasspack mufflers in the tailpipes.  I was using 3-chamber Flowmaster mufflers which are reasonably quiet.  The exhaust was fairly quiet, but there was no hiding the sound the headers made.  Even switching to thicker tubing still produced the distinct "plinking" sound of the gasses popping into the primary tubes.  The cam had a good bit of duration and lift, but further had a lot of overlap and at anything under a 1000 rpm idle, had a noticeable lope.  I would expect that there are no cams for the 6.9 that are even close to what I used on overlap, so the "4 mufflers and a crossover" approach should keep things civil.

Not surprised about the throttle body... they always looked awfully small for a 7-litre engine.  The intake ports seem tiny too, but that's another discussion entirely.  Naturally, all designed for substantial part-throttle torque.

gf

Wow Geoff! thats awsome! I had no idea that there was so much scope to hot up old engines to that extent! Do you have any idea how much your 0-100kph time has been cut by?

motec6.9

Hi guys I hope anyone thinking off doing there own exhaust reads this article I posted as it will be useful in giving them the information needed to make informed choices . Geoff  :)
Euro 6.9 255.6hp at the wheels. Watch this space.

Tony66_au

WoW!

Near enough to 300 neddies is impressive, any idea on the torque figures?


GF your mate is correct, let a car breathe properly and you get performance.

Air/fuel in plus Exhaust out..........

Yes its a balance and you do have to do your homework but a decent exhaust system makes a world of difference.

Geoff however has taken it to a new level it seems lol

motec6.9

Hi Tony as the original dyno report shows with the extractors and efi it never went under 600 foot pounds of torque. So that is the real increase but I would not do it again as the cost was over $15000 for motec computer all parts needed and extractors plus exhaust. Geoff :)
Euro 6.9 255.6hp at the wheels. Watch this space.

ZCarFan

I recall reading an article that specifically covered the concept of the termination box in some depth.  Was some time in the early 90's.  I'll see if I can find it.  I have doubts about it being available in electronic form however.

Tony66_au

Quote from: motec6.9 on 15 October 2012, 07:34 PM
Hi Tony as the original dyno report shows with the extractors and efi it never went under 600 foot pounds of torque. So that is the real increase but I would not do it again as the cost was over $15000 for motec computer all parts needed and extractors plus exhaust. Geoff :)

OUCH!

But I reckon thats not bad for the huge grin it would have  given you!

600 Ft-lbs is massive torque though