On a crab'd 3.0...how much backfiring is "normal"?
 

Ok when I drive my car in the morning, I start her up and let idle at 1500 rpm for about a minute.......

Then I start driving, and she will fart fat ones for about the first 3 to 5 minutes of driving, then she settles down ..........also if I gun her and then down-shift she will fart quite a bit.........

My heat-exchangers are new ssi's so the problem is not there...Also TRE did a rebuild on the carbs.

Keep in mind that in order to run carb's on a stock 3.0, they need to be run rich.

Is this normal behavior?

thanx,

SvK

Bob Tilton,

Does your car do this?

SvK

tansplanting the heart of a beast will involve dialing in little nuances over the course of time as you re-adjust to a new organ.

i had this issue and several others which took about 1000 miles to resolve. my back firing was the result of a lack of back pressure due to the dansk duel out sport muffler. i replaced it with a single out dansk and the problem was solved.

in re: to start-up, the carbs need about 30-60 seconds at 1500 rpm to clear its throat(s) first thing in the morning. it's fine once i take off. all other start-ups are fine.

have you cked for exhaust leaks? i had one at the SSI flange to the muffler flange. Resolved with new gaskets.

how's your engine temp?

Bob the surgeon ;-)......thanx for responding

my engine temp gauge is always super low.....maybe broken?

btw, I have single-out Dansk....will check muffler gaskets....

SvK

"in re: to start-up, the carbs need about 30-60 seconds at 1500 rpm to clear its throat(s) first thing in the morning. it's fine once i take off. all other start-ups are fine."

So when you drive to work and leave car for 8 hours, then start up for drive home,,,,no back-firing?

SvK

yes - i recall from your pics that you had a single out exhaust.

what you did was a major upgrade with a lot of things done at once. 99% of the work has been completed and only time will tell what that 1% needs to be done.

sounds like it just needs some fine tuning which is to be expected.

what are your thoughts on the suspension?

Love the suspension.......she is so stable at 110mph........you gonna upgrade?

SvK

yeah - all other start-ups are fine after the morning start-up which is also combined with a couple days of sitting. it was much like my '83 rx7 which required the same start-up procedure.

On a crab'd 3.0...how much backfiring is "normal"?

"Crab'd"

In this case, I suggest you take your car to one those free clinics; not TRE...:D

i can't justify the susp upgrade right now considering everything is new "down there".

my next upgrade will be a LWB ST replica. ;)

Wish I could give you more feedback on suspension.....I am not a schooled driver YET....so I take it pretty easy in turns........But like I said , Night and Day difference at high-speed..

BTW Dave at TRE said: "The '68 suspension was just plain awful"

SvK

I think that includes the prior year as well.......

ST huh ?

" ST/GT was permitted to run an oversize engine for racing in Group 4, the FIA allowing Porsche to increase bore but not stroke. As a result, displacement was up to 2247cc, bore having been stretched by 1mm (to 85mm), stroke remaining unchanged at 66mm. Designated Typ 911/20, the highly tuned engines were equipped with twin-plug heads, camshafts from the Carrera 6 and special Mahle pistons."

wow.......what color? ;-)

ST rear...for Surgeon Bob,

http://forums.pelicanparts.com/uploa...1125117731.jpg

these are my initial thoughts as i have just been having them within the last few days:

1 start with a carerra and backdate it
2 69-73 front fenders
3 plain front bumper (not split S or RS)
4 1 piece rear bumper
5 fuchs up front, minilites in the rear
6 cibie hood lites (2 pair)
7 RS interior with dark green leather
8 slate grey exterior
9 no decals

this would require selling my car and starting new.

it will be interesting too see what your car will fetch.....but how will you live without a working Porsche during the build?.....that is just torture. Just a mere 6 weeks without my ride and I was ready to start Prozac...

SvK

DD74,

heheheehehe...i couldn't figure out what you were talkin' about

"crab'd" ....free clinic ! hahahaha


....but my car is suffering IBS ;-)

SvK

So, umm... What happened to the CIS injection that came with the 3.0? You could always 'uncrab' yourself...

ianc

all below depends on ignition, cam, etc.

the gas has to be in a state for efficent combustion. CHT becomes a factor with a rich idle circuit. I've found that a very rich circuit needs a bit higher CHT than just a rich circuit to preventing start up bs. Very rich needs about 175degF for no bs at all, rich needs about 160degF.

Ronin,

I have no idea what you are talking about ;-)

Please speak english...so this dummy can understand........

SvK