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Topic: Looking for a little 305 tech help
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Page 1 of 1 of 12 replies
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April 19, 2007 at
01:29:37 PM
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11/30/2004
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I'm helping someone with an injected 305, and we're thinking he's off somewhere on the motor tuning. Right now here is where it is....
Timing 42 degrees
.090 in the main
54 lbs on the high speed with .108 in it
DSR fuel pump flows 1.8 gpm
#16 nozzles
Heads are basically stock, 11:1 compression rule.
no rpm out of the motor....just seems way too lean to me, but I've never done anything with 305 motors before. I know it's lean....this past Sat he raced in about 40 degree weather and got to about 220 every time on the track with no tape or anything on the radiator. Headers were turning white. Car takes off good....I'm just wondering if he needs to bump the high speed pressure up about 10 lbs or something to start off with. No RPM out of the motor....kept throwing gear at it, but never gained any. It just seems like he's starving the motor of fuel at upper RPM to me. Anyone with experience in this series with info would be appreciated.
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April 19, 2007 at
02:21:17 PM
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Im fairly new to the 305 game myself, but I know cooling has been a problem with some of these engines. It does look like your numbers may be off on the fuel system, but I am no expert and I know each setup is different.
Im not going to start throwing out numbers, because I simply just dont have knowledge.
email me if you want to talk about setups....or ignore me since I dont know very much...haha.
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April 19, 2007 at
02:43:15 PM
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Ha Ha....thanks for the reply Slow....but setups aren't the issue. We just need to get the motor tuned better than what this guy is recommending for him.
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April 19, 2007 at
03:40:12 PM
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Well I meant fuel setups...but its cool no problem!
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April 19, 2007 at
03:49:39 PM
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We ran a 82 in the high speed at 48 pds and anywhere from a 78 to 84 in the main. Timing around 36 degrees. With the wing on the 305's they always seemed to run a little warm. It was hard to get your arms around the fuel. The best luck we had was in that range.
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April 19, 2007 at
04:09:18 PM
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ahh, sorry Slow...didn't know that's what you meant! Hootus, that sounds a little closer to what I had in mind....especially with the timing. Hopefully some of the comments we've gotten back will help us to land him a little closer.
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April 19, 2007 at
05:01:00 PM
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Hey no problem, but please consider.........
Your pump is large for the 305 world
Your nozzles are huge compared to what it seems like "everyone" is using
The less advance, the hotter it will run in basic engine theory.
What works for hootus, might burn you down! Have you ever had your fuel system flowed?
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April 19, 2007 at
08:18:48 PM
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i think you have to much timing with the mag but there are also a lot of variables that no one knows like : what rpm is the cam good to, what about valve springs, what is the cam timing set at, is the ignition good , has it been tested, was the engine dynoed or just assembled and stuck in the car that dyno money is some very well spent money as it saves a lot of time driving back and forth to the track to try and get it to run 4 or 8 laps at a time and like slow said has the fuel system been flowed and so forth just my 2 cents worth
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April 19, 2007 at
09:51:15 PM
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Slow, you're right.....the pump is pretty big for a 305, and the nozzles are WAY too big for his motor....but he's got what he's got. We fired it tonight, and it sounds much better....went to 36 on timing with 84 in main and about 50lbs on high speed with 90 in it....gonna try it that way. Maybe next year it'll be 12 nozzles and we'll end up at about 60 main and 60lbs high with about an 80 (that's a hell of alot closer to what I'm used to!). Crewchief, yes basically to every question (I don't know what the hell the dyno guy is thinking, but I think the way he had it is pretty much crap). Everything is good, I know that. We'll get it, I just needed some help getting him into the ballpark. Thank you all for your help!
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April 19, 2007 at
10:12:49 PM
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Seems like a lot of guys will dyno a motor, but how many of them know how to tune a mechanical injection?? I have been trying to find someone to dyno my engine, they all say YES but told me later they usually have to "call a guy" on the fuel systems.....
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April 19, 2007 at
10:46:22 PM
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This message was edited on
April 20, 2007 at
11:38:16 AM by stealth14
Reply to:
Posted By: slow_sprinter on April 19 2007 at 10:12:49 PM
Seems like a lot of guys will dyno a motor, but how many of them know how to tune a mechanical injection?? I have been trying to find someone to dyno my engine, they all say YES but told me later they usually have to "call a guy" on the fuel systems.....
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way off on all of it. The nozzles are fine nozzle size only determine the quality of the atomization, the smaller the nozzle the better the spray quality but you need alot more pressure to acheive it. so here timing 36 main pill start at 75 and set highspeed at 85# with a 50 pill trouble you are having is the highspeed is open all the time so there isn't enough pressure to push enough fuel to her. this will work if your mag is in fair shape. Also unless you have an msd no more than .018 gap on the plugs with SOLID CORE WIRES. hope this helps also start out with the barrel valve at around 18%
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April 19, 2007 at
11:33:57 PM
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Well there ya go..I knew someone who knew something would post eventually!! haha
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April 20, 2007 at
07:52:31 AM
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This message was edited on
April 20, 2007 at
10:43:27 PM by crewchief47
slow where are you at there are 3 or 4 engine shops within an hour of my house that know their stuff on injections i am in northwest ohio 419-721-1778
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