carb starvation in corners

RWebb · RWebb's Garage

I'm wondering what cars had this problem?

Did old Porches ever have it? When GM intro'd FI, they listed that as a problem their fancy new system overcame. I'm wondering if it was more of a problem with American cars or not...

RWebb · RWebb's Garage

so, has anybody experienced this in their old Porsches?

widebody911 · widebody911's Garage

I've had the problem in my 911, although it's not carbed. The worst is when running Thunderhill backwards, going up turn 5, on less than 1/4 tank.

bell · bell's Garage

I had that problem in my turbo omni when autocrossing on less then a 1/4 tank......that would be more of a tank design flaw than anything.....
If a carb'd car did that in the carbs it could probably be overcome by raising the floats in the bowls along with the overflow tube.....

javadog · 03-11-2010, 01:20 PM

Early carburetted Ferrrari 308's can suffer from this. It's often seen on engines that were mounted sideways, like in a 308.

JR

masraum · 03-11-2010, 02:23 PM

Right, so there's 2 different kinds, right. One kind is fixed by adding baffles or open cell foam to the gas tank, and the other is fixed by modding the carb. I've had issues with the gas tank, but never the carb. I've heard of issues due to carb design, but never had them myself.

dd74 · 03-11-2010, 02:37 PM

I always thought it was a side-draft vs. down-draft problem (w/ Webers).

Shawn 357 · 03-11-2010, 02:43 PM

You can have this problem when on extreme angles but we are talking rock crawling stuff.

onlycafe · 03-11-2010, 03:02 PM

i had a covair that ran a single holley four barrel that would run out of fuel in tight corners.

sammyg2 · 03-11-2010, 03:26 PM

Some old muscle cars with holly 4 bbl carbs had this problem if they had the side hung floats. They updated most of the higher performace carbs with a different bowl assy with center-hung floats and that pretty much took care of it, as long as the float bowl setting was on the high side of the tolerance. That sometimes led to sluggish idling but at least it didn't crap out on top end. that's the only ones I am personally aware of.

javadog · 03-11-2010, 03:29 PM

Quote:

Originally Posted by dd74

I always thought it was a side-draft vs. down-draft problem (w/ Webers).

It was a problem in down-draft Webers mounted laterally.

JR

sammyg2 · 03-11-2010, 03:31 PM

oh oh oh, I just thought of another one. My oldest brother bought a new BMW 318i a long time ago and he called me to come look at it because he thought he screwed it up. It would start and barely idle, really rough. It wouldn't rev worth a crap. I checked over a bunch of stuff and started asking questions.
it turns out he was hauling butt on the freeway and took the off-ramp kinda fast, and the fuel tank was less than 1/4 full. Closer to 1.8th tank.
All the remainibng fuel had sloshed away from the pick-up and he sucked air into the injector lines.
I started the car up and gave it gas and held it at around 3000 rpm in neutral for about 10 seconds, and it cleared right up. I told him if he was gonna play rickey racer he needed to keep more gas in the tank.
That was prolly in the early to mid-90's or so.

RWebb · RWebb's Garage

apparently, people who raced Ramblers (really!) had this problem also...

onlycafe · 03-11-2010, 04:38 PM

i will try to find a good rambler racer story about my friends father. [going to look now.]

javadog · 03-11-2010, 06:02 PM

Some BMW's had a tank with two pumps. The second one was a transfer pump, to transfer fuel from one side to the other (over the driveline hump) and if this pump fails you can run out of gas in a really hard corner, usually on the track, if you run below about a 1/4 tank. You can trash rod bearings in an E30 M3, from lean mixture-induced detonation, quicker than you can read this sentence.

JR

Vern Lyle · 03-11-2010, 06:41 PM

Back in the late 80's, there were three of us in carbed 911s doing Pro Solo and Divisional Solos on the east coast. Kinda all of a sudden, we all started to suffer from hesitation on hard corner exit. In retrospect, it was about the time we all learned how to maximize the use of the Hoosier Autocrosser. We all tried everything, getting down to carb mods by a new outfit called PMO. Worked some of time, but frustrating enough for me to park the car for a good while. Their mods since those early days are probably more effective, I don't know. I have not run carbs since.