Hi pontiac 301T

[canadian nascar]

Hi Guys,

I am putting on a magnaflow manderal bent cat back on and was thinking of not using the mufflers and going straight pipe to the back. I have 2.5 dp and this system splits to dual tail pipes, 2.5 front to back.

Will NOT using mufflers cause it to lose power because of lack of back pressure?

It would be simpler to put the mufflers on but I don't want to find out that they are restictive. I want to sell them if they are not needed.

BTW still tuning and I am happier with the way it is running, tuning sure takes a long time to sort everything out if you are a newbie

later Kevin

 

[WarWagon]

Your turbo is a muffler and it is creating back pressure in it's own right. You will not lose power by going straight pipe, may gain a psi or two of boost and quicker spool up and of course raw v6 noise!
Go straight pipe.​

 

[canadian nascar]

Thanks War Wagon,

I am actually a 301t user, I thought that would be the answer but wanted to make sure.

later Kevin

 

[John at J&S]

I think the misfires were causing engine noise due to uneven firing events. This probably caused engine noise that was interpreted as knock.

I don't see how fresh plugs can clean up real knock.

 

[canadian nascar]

car is running really good, idle almost perfect, the issue of breaking up hasn't been ther for awhile now so between new plugs regapping and dialing back the vac. adv it is more constant and great power until heat soaking sets in.

new exhaust is in with cat delete pipe, kept mufflers, kind of quiet though, stealth or pussy cat that pulls

later Kevin

 

[canadian nascar]

hello friends,

well still struggled after my last posts with knock, sigh,

so this year no j&s as stock ignition as possible,

I have it idling great no two foot at lights, no gassy exhaust, i

but now it will only boost 5lbs, aaahhh, pulls normal but actually feels stronger than 5lbs

timing stock weights and cam ignition, 20* max mech plus vacuum, not sure idle timing. responding and operating better without weird hits of knock, i had it locked

I have had spectacular moments but always weird knock, have spooled fast and spun nitto 275 50 15 at 30mph

1 looked at turbo exhaust wheel looks fine
2 need to lift turbo to check waste gate puck for sealing
3 I don't think secondaries are holding it back
4 change and inspect all vacuum lines
5 possible boost gauge acting weird, feed line issue, but vacuum seems regular
6 could my coil cause issues?
7 inspected boost controller seems fine, could bench test

any other thoughts

was put away last fall spooling fast to 15lbs, now spools quick to 5 but stops even tough feels stronger than 5lbs

so frustrating, Kevin

 

[canadian nascar]

So boost is back,

my 4 yr old daughter has been my co pilot, she been asking if the rocket boosters are working, lol

I would put the issue was the choke was hanging up the secondaries,

changed all the vacuum lines.

you guys would be amazed on the 301 power, dialed the boost controller down but still have more tuning again.

Later Kevin