Hi everyone, especially ones with same engine (3.2JTS) and Q4!
for some time now am having wish to bring the exhaust of this beautiful car to the level it deserves, since feeling that the car is too much restricted by 4 cats and bad pipework
so the ideas are as follows:
change the headers to something like Autodelta offers, with removed pre-cats and equal spaced pipes
after lambdas X pipe section for increasing the flow through the system (pic hereand here and here), more explanations maybe here
after X pipe section would be nice to have new, slim middle mufflers (do not like cheap & loud :tut:, more good but low level sound :thumbs, something like thisdirect flow mufflers
after passing the bends around rear axle differential, coming to the new rear mufflers, again direct flow version
at the very end, all camouflaged to the OEM tailpipes
now, the problems are as follows:
central funnel is very cramped, with purely positioned axle towards left side (think that it would be easier if positioned more centrally
am not sure how to proceed on this one: should I use the factory diameter pipes (think it is 65 mm) or try to tune in 75 mm (3")?
is there any other method for noise lining middle section instead of middle muffler (wrapping in something?) or simply to do the most of the noise lining at the back?
additional thought came to mind: maybe to remove the complete reserve wheel "bucket" and leave the full volume for the one jumbo muffler which could utilize active change between direct flow sport mode and heavy muffled normal mode?
where noise lining has to start and is the middle muffler really that necessary?
on next photos you can see how it all looks down bellow
and, yup, am engineer that is why started playing in CAD system (for the moment only basic models are prepared for final shuffling)
does anybody knows the firing sequence by 3.2JTS V6? I have found somewhere that firing sequence for GM V6 engines is 1-2-3-4-5-6, but am not sure is that true for 3.2JTS
please be as detailed as possible in descriptions:
First precisely describe which piston (see attached photo; A,B,C,D,E or F) is which one in firing sequence (but oriented as shown on attached photo, for easier orientation)
Would be ideal if you know at which angular position of the crankshaft which piston fires
Do you know does full firing sequence happens in 2 full turns of crankshaft (4 stroke cycles) or is different?
Do you know at which angles (please be precise, in full interval of 720 deg(2 turns of the crank shaft))
should I understand the "front of the engine" from your link as side where all of the belts are? in that case in my Alfa that would be the right side
just noticed that schematic shows 1-3-5 on "right" & 2-4-6 on "left", while text above it names 1-3-5 on "left" & 2-4-6 on "right"; or is the schematic view from the bottom? please clarify this
is there somewhere information about the angles of the sequence?
many thanks for this information, is very useful for thisproject. the most important bit is to know that succeeding firing is always on the opposite bank. this makes life for double pipe exhaust good case and should give nice "stereo" sound at the back
Yeah there's a mistake in the text. They don't know their left from their right. I'd guess it's just a scan from autodata or some other generic technical guide for mechanics.
Not sure what your query is about angles. Assuming it's an even firing engine, cyl 1 will be at TDC on the firing stroke at 0 deg, therefore cyl 2 will follow 120deg later, cyl 3 another 120deg later, etc. Of course the actual firing position will vary by maybe 40 deg or so depending on how much advance/retard is required.
this is what I was looking for! the important is that cylinders on the same bank do not have firing sequence just after each other, meaning that is good to know that first fires piston on one side bank, then other. that should be good for the exhaust and performance.
as Sussexa triggered in Jaba's forum here, it would be good to add the eVac scavenger in the system, when we are already building new exhaust.
now, since we are building double pipe exhaust routing the question is where in system to position the eVac scavenger:
if placed on one of the pipes, then vacuuming will be available only in 1/2 of cycle
maybe middle of the X-pipe would be a good place since affected by flow from both banks? middle section of X-pipe might be good also, since we would add obstacle to the flow (eVac) in the bigest cross section area (due to transitions), which means that air flow velocities should be smallest and therefore the losses smallest! unfortunately, reduction in air flow speed means increase of the pressure which will reduce the driving pressure difference of the eVac system
alternatively, we could add double eVac (just before the eVac plugs add Y section)?
where is the best position for the eVac "axially" in the system, before or aft the CAT? if in front of CAT, it could help burning the oil mist and having cleaner environment. but, could it cause a fire? can anybody answer this question?
it is exhaust pipes equalizer, since our V6 is mounted transversely. this means that front bank has allays bit longer pipe than the one from the rear bank
Japanese tuners got idea to add pig-tail in between the manifolds and CATs
very nice idea, was really surprised to see how much far away are Japanese tuners in tuning ARs than here (the most tuned AR159s and Breras I saw in Japanese videos on YouTube)
even the headers look excellent!
SMALL ADVICE regarding visiting their web site
since most of useful information in Japanese, you'll need some "blind" navigation through it:
by first entrance, use only the links at the top of the page, just right from the sign ORQUE, select TUNE UP PARTS
on next screen select AR
then the model of your car
after that for you important area is inside the red dotted rectangle
all parts are split in 3 categories:
exhaust, engine & power-train
brakes, suspension & reinforce
electric & appearance
each link has few sub-pages
use your intuition and enjoy
current exchange rate is 1 yen = 0.0071 EUR = 0.0056 GBP
here is animated explanation of the Flowmaster muffler who's cross section you see in post above
and here is animation showing their laminar flow muffler
to my best understanding of the topic, it seams that laminar flow should/could be used as center-pipe muffler (is compact enough to be mounted in funnel, next to the shaft), while the upper mufflers should be installed as end mufflers (their effect of further reduction of the pressure at the end side should increase the suction effect from engine)
good news, Powersprinthas introduced very compact (small diameter; biggest is only 114.3 mm, smallest starting from 70 mm) mufflers series "Missile Racing" which should be very good for our cramped funnel:
damn, who needs mufflers when all sounding such a good :biglaugh: ?
well, TÜV/MOT for sure :readit:
well, think that similar, with addition of previously mentioned direct flow mufflers Missile Racing from PowerSprint would be solution for me. of course, Autodelta headers, EURO5/6 sport cats, X pipe and dual pipe all the way :thumbup:
or, one starts thinking loud, if we put valve and organize as by pass this straight through pipes for sport mode?
I have a straight-thru pipe on mine with centre silencer & rear mufflers (Alfatune) which makes the car really loud. I mean really loud, without mufflers on i can only imagine the noise level would be to intrusive to the cabin which would probably become tedious after a while.
Be wise when having an exhaust fitted you may find the standard exhaust is more pleasant on the ears
Just spilt my tea when I saw the price of those autodelta headers £1500+!
I like all the idea's you've researched, the equal length primary pipes look nice and 200 cell cats and X pipes, I'm alittle worried about you getting two 2 1/4" or 2 1/2" pipes snaked between the fuel tank and prop bearing carrier, see pic? Looks too tight to me, I found it hard enough to snake just a single 3" pipe on my home made system with no prop so makes me think its too tight.
But yes got to agree Ozi's V6 with rear silencers delete sounds very impressive. So what about this for an idea and bearing in mind your concern's for your exhaust to look correct for TUV. How about replace the center silencer for your Flowmaster or a Vortex (for improved exhaust scavenging) and then have a couple of these rear boxes with electric valves in: Exhaust Muffler with Electric Valve Silencer
The motors are on the top so out of sight from TUV tester (fingers crossed) then you have quiet exhaust for driving Grandma to the shops and loud/same as Ozi's with valves open.
in general like the idea of sport sound ON/OFF, but there is something seriously metallic rattling in the sound of that video, do not know if something is loose there or not
regarding the snaking around the fuel tank and prop bearing carrier: that section could be done using flexi exhaust pipes. from straight piece of centre section till the end mufflers one could use flexi pipes. no worries for differential thermal expansions as well
Hi Filbyboy, that Alfa has few more things than just headers and exhaust: MarioDesign has done few more important tweaks, like new camshafts, more serious brakes etc.
Yeh i Looked at the 159 ages ago. I knew it had a lot of work done to it with the cams. You can hear them. The Rev range is also seems higher.
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