Guest Anonymous Posted December 22, 2000 Share Posted December 22, 2000 Every time I go to the dragstrip, I end up with this same problem, no matter what I do. Well, here's what happened. I was running against a friend for some testing to see if I could fix it before picking some races with the local ricers. Well, I find an integra with a big huge spoiler, clear tail lights, and I find out he's shootin gas. Anyway, I line up and the light goes and I hit it. The front lifts up so that the front tires are about to lift off the ground (h rated street tires). Well, after this LEAP off the line, the car falls flat on its face like down to 50 rpm as if it's going to stall. It comes back to life as I stand on the gas in desperation. I hurdle down the strip to catch this nitrous integra. I pass the traps in 14.1 seconds at 101 as the integra goes to a 15.1. I won, but this is very disappointing. 14.1 in a V8 Z? Any ideas what the problem is? It's a 260Z with a 78 Monte Carlo (emission days) 350 with a TH350 and R200 rear. The carb is a small edelbrock 4 barrel. Other than a very mild street cam, the engine is stock. I have messed with timing a little and carb a little, but I need like a step by step proceedure to fix this if someone knows. Thanks. ------------------ pics of my babies at www.rotarypowered.com/cym and at www.dodgeviper.net/260z Quote Link to comment Share on other sites More sharing options...
Guest pauli Posted December 22, 2000 Share Posted December 22, 2000 i'm reminded of a story a guy i know once told me, about how he had a late 50's chrysler at one point that made a ton of power and was really fast, but you had to drive it right. he said that if you stomped on it off the line it would flood (or something, i don't remember well this late at night), and occasionally stall. try a lighter launch. might do the trick till you fix the problem. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 22, 2000 Share Posted December 22, 2000 I have tried lifting off the gas and easing into it. Even a street start it does it... I don't know what it could be. ------------------ pics of my babies at www.rotarypowered.com/cym and at www.dodgeviper.net/260z Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 22, 2000 Share Posted December 22, 2000 hi well i may be saying somethign stupid but if it helps hey. i had similar probs with my z on the launch. when i would hit it from the stop it would bounce but suddenly seem as though it shut off and just as i look down to see the rpms it launches and goes. i fixed this by an obvious off the line procaution. dont be affended if i say this and it is something everyone would know or stupid. i rev it to keep the juices flowing just a little till the light changes then stomp it and it no longer boggs. i believe it would maybe at idle have a little too much gas in mixture so when i stmped it it really overwelmed the carb. so hey it that helped cool if not my excuse is im a kid and have little knowledge. bye bye Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted December 22, 2000 Share Posted December 22, 2000 Ok, I'm going to add another stupid question... Are you 110% sure that your floats are set high enough? I had a similar problem that stumped me for weeks on end. Everyone would ask me "Did you check your floats?" I always told them yes. Well, one day out of desperation, I checked them (as a sanity check). Way too low. A few turns of a screwdriver and all was well. Sometimes, the solution is so simple, it's sitting right under our noses. -Andy Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted December 22, 2000 Share Posted December 22, 2000 Also how much gas was in your tank? If you didn't have much, when you launch, the gas goes to the back of the tank, the pick up is at the front. So you may be starving the engine of gas for a short while. ------------------ http://members.tripod.com/~SnowSurfer/mikekz1.html Quote Link to comment Share on other sites More sharing options...
Guest Daddyrick Posted December 22, 2000 Share Posted December 22, 2000 No matter what you do, if you are going to race your z, install a fuel pressure gauge. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 22, 2000 Share Posted December 22, 2000 I had about a half tank of gas in the tank. I think that that should be enough, but I'll try more next time. I will check my floats and installing a fuel pressure gauge is a good idea. Thanks. ------------------ pics of my babies at www.rotarypowered.com/cym and at www.dodgeviper.net/260z Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted December 23, 2000 Share Posted December 23, 2000 Firstly, is it the edelbrock 1406? Either way they have a VERY GOOD tuning manual for all their carbs and it's online in complete form at www.edelbrock.com. A bog is either too little ignition/not enough fuel/too much fuel. Have you played with your acc. pump lever arm at all? Should have 3 notches and you can try a notch closer to the carb for a bigger shot and further away for a smaller shot of fuel. If you do have a performer series setup the WOT phase of the metering rods is actuated by vaccuum signal acting on the metering rod springs. Edelbrock explains this in their guide. You switch to the lightest or stiffest spring and if it helps then progressively step back on spring pairs till the bog returns/go back to previous pair and that's optimal. Do you have enough initial timing into the motor? Chevies usually need min. 12degrees BTDC and often more. What are you running? How are the secondaries on your carb activated? If they're vaccum they should be fine (I assume they are). Carbs can get a bad name easy as they're easy to 'poke at' without getting into manuals but it's hard to nail them down without learning up on them. Most EFI users make a sizable investment and HAVE to read up to tune their stuff hence some of the discrepancies. Also make sure you don't have any vaccuum leaks as well. (and as mentioned it's always good to know your fuel psi is correct for the carb as a starting point) Quote Link to comment Share on other sites More sharing options...
Guest MistaFosta Posted December 25, 2000 Share Posted December 25, 2000 Are you running the stock 5/16 fuel line? It seems to me that that is horrendously small for any v8, especially a pumped one.... Dunno, sounds more like an extreme starvation problem than a rich mixture...Does it puff a nice black cloud after the launch? Quote Link to comment Share on other sites More sharing options...
johnc Posted December 27, 2000 Share Posted December 27, 2000 If you're running a Holley 4 barrel this sounds like a classic power valve problem. The engine makes power on the initial squirt from the accelerator pump but then bogs waiting for the additional fuel flow that the power valve is supposed to provide. If you've ever run the engine lean and had it backfire through the carb, the power valve is probably blown. Or maybe you just need to try different power valves to see which works best on your engine. Oops! I just read the original post a little more thoroughly. Igonore my irrelevant Hollay post... ;-( ------------------ John Coffey johnc@betamotorsports.com [This message has been edited by johnc (edited December 27, 2000).] Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted January 1, 2001 Share Posted January 1, 2001 Accelerator pump shot is what I would look at. It sounds like you're using all of it before the engine gets going. Don't know about Performer (isn't this like a Carter?), but Holley's allowed you to change the pump cam/reposition the cam to deliver les/more and affect the timing during the stroke (where the highest volume delivered occurrs in relation to accelerator pedal travel. If I had to guess, I would think that you could slow down the initial delivery and make it last longer. Hope this helps Quote Link to comment Share on other sites More sharing options...
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