Exhaust fumes in car

[KenB]

Over the past few weeks, I've had the opportunity to ride in a SuPerformance and a DRB. Inside both cars while we were driving, there was a strong smell of exhaust fumes. One of the cars had the full windows in with the a/c on, while the other car had no windows in it.

Is the heavy exhaust fume 'fragrance' typical in most GT40's or did I just happen to hitch my rides in a couple of smokers? The owner of the windowless DRB told me, it was due to the back draft the car produced upon acceleration and referring to the exhaust smell, he said, "it comes with the car, it's part of the car".

Thanks....

 

[Seymour Snerd]

Over the past few weeks, I've had the opportunity to ride in a SuPerformance and a DRB. Inside both cars while we were driving, there was a strong smell of exhaust fumes. One of the cars had the full windows in with the a/c on, while the other car had no windows in it.
..

Ken's experience with the SPF car interests me in particular; regardless of what the exhaust was doing at a stand-still, in motion with windows closed and A/C on I would expect the in-cabin fumes to dissipate pretty quickly.

Unless.....is this possibly another result of all the openings at the rear of the SPF cabin? The one I wonder about in particular is the shifter shaft tunnel that opens near the rear of the block. If you have a cable shift, that path is completely open (unless of course you took measures to block it).

Have any SPF owners who water- and/or heat-proofed their cars noticed a reduction in exhaust fumes?

 

[Steve C]

Alan,

I take P2125 for 2 hr drives and don't notice any fume issue (fuel or exhaust).

Steve

 

[Jim Craik]

Alan,

I have put over 25,000 miles on P2264, I have never smelled exaust fumes.

I have put Dynomat and a plastic bubble wrap type stuff for insulation.

Additionally I have foamed the central tunnel, but I put 2,000 miles on her before I added these products and I did not smell any exaust.

 

[Seymour Snerd]

Jim and Steve --

Thank you guys. Needless to say that's what I wanted to hear, but it's also what I expected to hear given my understanding of the physics and aerodynamics of the situation, and knowing how well constructed your two cars are.

By way of explanation, the SPF in this situation is Lance's black demo, and I was with Ken the day he took that ride (although I did not take a ride myself). The car has a Roush 427R (the hairy one), and it has one mean sumbitch idle.

They started the test ride with the car parked in the shop, with both car doors open, fired it up and let it idle for probably 5 minutes. Now I can tell you that between the fierce valve overlap of the engine and the semi enclosed space I was almost asphyxiated just standing there.

(Editorial comment: the audio-visual impact of that thing shaking its doors in response to the crazy idle is enough to make you order one up on the spot. It looks like some cokehead pterodactyl about to hit critical mass. All part of the sales pitch, I guess)

Anyway, still I would have expected the fumes to get cleared out during the test drive since Lance was driving fast with the A/C on. So I'm suspicous that the car hasn't had all the orifice plugging that it needs. Next time I'm up there I'll check.

OTOH, I also know from working on cars with high unburnt hydrocarbon output that half an hour later I can still smell it in my hair and clothing. So I'm not sure even a brisk ride afterward would correct for the "starting conditions" that day.

 

[Ian Anderson]

Aircon may not clear the fumes

Normally aircon just recirculates the air in the cabin and you would need some sort of air input from the outside to force the fumed air out of the cabin.

I have this on my car too (Dax + radical cam) and find the fumes manage to get in through all sorts of areas
Gear Lever (rod tunnel)
Hand brake (center tunnel)
Around engine hatch (now sealed)
Around bulkhead window.

Having a constant flow of air coming into the cabin from the front of the car reduces the fumes to only when stationary / in extremely slow traffic - and in those situations I run a blower to keep the air moving
(I don't have aircon)

I have also heard that openign the rear exits either side of the exhause allows more air to exit the rear clip when moving and again means the fumes tend to move rearwards from engine instead of forwards into cabin

And yes clothes smell for ages afterwords

Ian

 

[René]

They started the test ride with the car parked in the shop, with both car doors open, fired it up and let it idle for probably 5 minutes. Now I can tell you that between the fierce valve overlap of the engine and the semi enclosed space I was almost asphyxiated just standing there.

Ah...I think thats it...
when I let my Hartge V8 on idle for a few minutes in my Garage even with the door and windows wide open, all smells like smoke/gasoline...
it gets in your clothes, you can do them in the wash-machine because of that, and that just in 5 minutes.
when you after that sit in your house on the bank you still smell it its in your clothes then and won't get out, you have to wash them, bin there done that a few times

I guess thats what happened, all stuff where smoke can get into or stick on (specially clothes) will get smelly for a period.

 

[Tim Kay]

ahhh....another one of the many wonderful facets of a GT40

 

[Paul W]

A problem I have discovered with the design of the 40 is that you get low air pressure above the door tops when driving which sucks the air out of the cockpit as well as lifting the doortops. If there are any fumes in the enginebay - ie leaky exhaust or even a rocker cover breathers they will make their way into the car. I had this problem on my car and finished up with my breathers exiting under the car so the airflow under the engine area takes them away. Obviously sealing up as much of the bulkhead area as possible helps as does allowing fresh air into the front of the car. I fitted a lower bulkhead fan to the left of my clutch pedal that sucks fresh air from the steering rack area.

 

[Kevin L]

At this point I think it is a feature, I augment the GT40 "cologne" with a few dabs of 10w-40 oil behind the ears; I think it adds to the experience


Obviously I am kidding. I have either gotten used to it or finally sealed up my cabin enough that there are no more fumes. Check that center sill area where the cable shifter goes through, it is like the grand canyon of air flow.

Kevin

 

[Mike Pass]

I don't get any exhaust fumes in the cabin of my GTD.If you are getting exhaust fumes in the car you need to do something about it as there is an issue with carbon monoxide in exhaust gases which is poisonous and will give you headaches at a low level and can make you dizzy and will kill if at a high concentration. I would look initially at the rear bulkhead sealing as the exhaust gas is making it's way from the very back of the car. There should be a good flow of air into the under rear clip area from the various intakes and the air should have plenty of outlets at the underside and rear of the car. If there is an airflow reversion issue with the rear clip then a few lengths of wool attached with water based glue should give you a good idea of air flows if you ride alongside with a camera - a lot cheaper than a windtunnel. We had a similar issue to yours with a Piper GTT which was solved by sealing the cabin, ensuring fresh air positive pressure in the cabin and opening up the rear bodywork outlets.
Cheers
Mike

 

[Seymour Snerd]

Aircon may not clear the fumes

Yes, if the Aircon is recirculate it just guarantees that the fumes stay in....

 

[Seymour Snerd]

Check that center sill area where the cable shifter goes through, it is like the grand canyon of air flow.

Just yesterday I relocated my LHS shifter cable up an inch, and was amazed to notice (again) the 1" hole they drilled for the cable, grommeted down to about 7/8" with the 1/2" cable going through. Not quite sure what the point of the grommet is; just to keep the pretty blue cable nice and pretty and blue?

 

[Jim Craik]

Alan,

I love your discription of Lance's beast! I have seen and heard it, kind of reminds me of the old Can Am cars.

One thing I noticed early on, I found that opening the little vents in the windows, makes the heat (and I'm guessing fumes) worse.

I found the when underway, the open vents create a low pressure area in the cockpit, that draws hot air in from the nose (you can feel it on your feet) and also engine bay fumes.

I always keep the window vents closed, this greatly improves the cooling in my car.

 

[Seymour Snerd]

...I have seen and heard it, kind or reminds me of the old Can Am cars.

I'm thinking of grinding play into my door hinges so mine will flop around the same way....:drunk:

 

[Steve C]

I too have found that just opening the "toll" windows does not give good flow through so now run with the "pop out (helo) vents and the toll windows open unless I need AC.

With AC I run outside air (not recirc) and all window pop out and toll's closed.

Works for me

Steve P2125