Dual x450's with model e's///pics fixed

Propane, Butane, LPG, GPL, C3H8, C4H10
C3H8
Posts: 1129
Joined: Fri Sep 09, 2005 11:23 pm
Location: Winnipeg, Canada

Re: Dual x450's with model e's///pics fixed

Post by C3H8 »

Its looking really good and sounds like you have most of the small issues cleared up. One of the things I am disappointed in is the VPV's, especially since I believe I am the one that suggested them. I'm a pretty firm believer in VPV's on a stock engine but yours is a unique setup. I must offer my apologies for that recommendation. One thing I can suggest prior to removing them would be a slight modification. As you probably are aware the VPV is shipped with a choice of 2 or 3 orifices. One for big blocks and one for smaller engines. In your case you have two VPV's for proper balance. This seems to over fuel the engine during cranking. One solution would be to make a custom orifice starting with an opening approximately 25% of the small one supplied and then enlarge it from there until the starting is right where you want it. A second option would be to use a single VPV with the fuel supply hose located into the adaptor centrally between the mixers and if necessary use a smaller orifice. This would save going to an electric set up and allow you to do slight modifications to your fuel curve at higher loads and RPM.

flatblack
Posts: 225
Joined: Wed Jun 23, 2010 7:42 am

Re: Dual x450's with model e's///pics fixed

Post by flatblack »

No big deal on th vpv's, im going to call monday to see if i can get the 4 cylinder orfices, I think the ones i have are the largest for the v8, if i can get the smallest one and run one it might work out for me. Its worth a try and they are real cheap, i think they are under 10.00 a pair shipped to me and 5 min to install..lol.

I would also like to install a low fuel light so i know when im close to running out of fuel. Not sure how tho that hooks up or even works, ill have to look into that and see what i can do. I run two 10 gallon tanks at a time and usually have two 8 gallon spares on hand. Its been real good on fuel with one carb but im not sure how it will be on two carbs. Time will tell tho when i get that far,

flatblack
Posts: 225
Joined: Wed Jun 23, 2010 7:42 am

Re: Dual x450's with model e's///pics fixed

Post by flatblack »

I ordered the smallest jet for the vpv, its smaller that 1/2 the size of what i have now. I was told its the 4 cylinder jet, that might actually work for what i need. I did get the low fuel light to go in the pressure line, since i turn one tank on at a time it will go on giving me time to turn the other tank on. Ill let you know how it works, it should be here tom or friday. Then after i get that all hooked up i can start running the new coolant lines.

gottago
Posts: 205
Joined: Thu May 24, 2012 7:39 pm
Location: British Columbia Canada

Re: Dual x450's with model e's///pics fixed

Post by gottago »

The vpv's should make an improvement with the dual mixers. With the vacuum signal to each mixer being split now, it stands to reason that the mixers would respond accordingly. I've had mixed results using them but never actually figured out why some engines respond well and others not. When they did work well, I had to tune and adjust to them, they didn't just help without some tweaking. You should have to lean out the idle mix a bit at least. Maybe even a slight bump in timing. You should see some changes to your a/f ratios with and without the vpv. You should go richer if they are working right. I mainly stopped using them over fuel mileage concerns, not performance or power issues.

It is possible that you have your mixers adjusted and dialed in so well for your engine size and combination that it compensates for the reduced vacuum signal already?

flatblack
Posts: 225
Joined: Wed Jun 23, 2010 7:42 am

Re: Dual x450's with model e's///pics fixed

Post by flatblack »

With the 4 cylinder jet in the vpv it still smells like fuel and just cranks. Disconnected it cranks and just fires right up, I can prob lean the idle mixture pretty far to get it to work like you said, ill give it a try when the rain stops. Should i put a tee in the ports in the one vpv and run it to both carbs or wouldnt that matter..? To be honest it idles, runs and drives pretty well. Ive been messing with the afr's. I did tune both carbs in seperately before bolting them on the adapter to make sure they did work real good. Also tried both carbs with the model e's seperately to make sure it was all good also. I did swap springs in the model e's to the orange spring and readjusted them with the tool to the correct setting. The only thing that hasn't changed is it cranks a few times before it fires up. When colder out around 10 cranks, when hot out a little less han that. No big deal tho it always been that way. Im guessing the only thing to do that is the electric primer or the sv start valve from impco, with the cable primer it helped alot but since its seen mud and water since the cables always froze or never works right.

gottago
Posts: 205
Joined: Thu May 24, 2012 7:39 pm
Location: British Columbia Canada

Re: Dual x450's with model e's///pics fixed

Post by gottago »

I think you have tuned it pretty well for a dual setup already.. When you set it up in the manner you did,
I did tune both carbs in seperately before bolting them on the adapter to make sure they did work real good. Also tried both carbs with the model e's seperately to make sure it was all good also.
Either mixer worked well with proper a/f ratio independant of the other. So now when you place both inline you split the vacuum signal and in effect the two mixers at half vacuum equal one at full vacuum. A/f ratio with two should remain close to the single at idle just a bit richer. Its the upper end rpm where the duals should be most noticeable. Starting can become tough.

When the vpv works right on a dual setup, starting does seem to improve and off idle response seems snappier. Upper end not much different. I'll be doing some work on a dual mixer truck in the next while and will be changing out winter cold start solenoids for vpv. Its a dual mixer/ dual vaporizer on a progressive linkage. I'm just going to put one vpv on the primary mixer. Will let you know what the afr number changes were.

You may want to try a splitter on yours but an on board af gauge/logger is pretty well a neccesity about then. You will have to adjust to compensate for the vpv no matter which way you tie it in. Its worth experimenting with it a bit but I get the feeling you are running pretty good now and don't want to deviate too far. Try to keep mixer settings fairly balanced. Record your settings so you can return to them easily. Keep an eye on your plugs. Sometimes you find a combination that works well with these, sometimes you don't. I've given up running them on some vehicles before. Nothing I did seemed to help with them. One little elcamino I had just loved them though. Why the difference? not real sure.. Let us know how it goes.

flatblack
Posts: 225
Joined: Wed Jun 23, 2010 7:42 am

Re: Dual x450's with model e's///pics fixed

Post by flatblack »

Ive been adjusting the afr by watching my digital wideband with heated o2 sensor. The metering rods are at a pretty good setting, when i first fired it up i had to Lean the idle mixtureand the idle speed. After that it seemed to run pretty well. A few things i can try tho : I can try the other washers i have for the top of the carb. Depending on the taper is supposed help rich or lean idle, I can swap one out and see where it goes. Then if it works i can order another one if needed. Ill lean the idle mixture out tomarrow afternoon and hook the vpv back up. I did notice when its cold i do get afr readings in the high 12s to low 13s, after she warms up i get in the low 14s at idle. Ive been running it daily and have put a few miles on it, so far the plugs look pretty good. If i get a chance ill pull one and snap a pic for you....Ill be gone in vacation for about 10 days so i wont be able to mess with it much...after that its game on..lol..

Im going to try to get the throttle response as snappy and quick as possible. Prob going to bump the timing a hair to see what happens. Im going to be converting this from a manual trans to a manual valve body turbo 400. So ill need the extra guts to get it moving as quick as possible. There is a few mud bogs coming up in july-sept, it will get plenty of testing/tuning etc. My small block usually keeps up with the race gas trucks, now thats in the same cubic inch range.

flatblack
Posts: 225
Joined: Wed Jun 23, 2010 7:42 am

Re: Dual x450's with model e's///pics fixed

Post by flatblack »

Ive been running this this around alot lately,ive been getting a hesitation when you step on the gas. It goes away pretty fast but its there. Other than that it runs great and has lots of power thru the prm ranges.

flatblack
Posts: 225
Joined: Wed Jun 23, 2010 7:42 am

Re: Dual x450's with model e's///pics fixed

Post by flatblack »

Its tuned in pretty good now, revs nice and clear and seems to have real good power. It still tho has a slight hesitation but clears up right away, i tried messing with timing and some afr adjustment but it seems the same.

flatblack
Posts: 225
Joined: Wed Jun 23, 2010 7:42 am

Re: Dual x450's with model e's///pics fixed

Post by flatblack »

Might have it fixed with more timing, have to give it a good run under load to make sure but so far so good.

gottago
Posts: 205
Joined: Thu May 24, 2012 7:39 pm
Location: British Columbia Canada

Re: Dual x450's with model e's///pics fixed

Post by gottago »

Sounds like you pretty well got it down to the fine tune fb. I've had better results using more timing than most would advize. In performance applications and especially with high compression I have been running the initial timing up quite high and slowing the mechanical advance rate a bit but still keeping under 30 degrees total. Cam dependant. Latest sbc at 250 psi cranking pressure liked a locked out timing of near 24 degrees up until about 2800 rpm after which 31 degrees locked out was best. Best compromise I was able to put together with available springs and trimming weights was 18 initial , 11 in mechanical and vacuum advance (manifold) limited to 12 degrees. Slow starting curve beginning at 1500 rpm all in by 2500. I'd like to tighten that up even more but its pretty good as is. Thats the thing on the fine tuning, there's always just a slightly better combination or so one thinks. Minor changes can be all thats needed.

I have several different aftermarket hei billet dizzys set up in different ways. I encountered one that had a built in retard function just off idle. Some sort of a module function I believe. It caused a minor stumble off idle acceleration. It wasn't sold as such and had no warnings or instructions for that.

Side note,
I did try the vpv on the big ford dual mixer setup. Took it back off 3 days later. Eventually used more initial advance on that one too. Slightly slower springs.

flatblack
Posts: 225
Joined: Wed Jun 23, 2010 7:42 am

Re: Dual x450's with model e's///pics fixed

Post by flatblack »

Going back to the timing, i didnt want to change the distributor but i think its time to swap it out for a hei. I can only do so much with this mallory unilite, 10 initial and 30 total is all i can get, After that the two go up together, next ill try the 12-32 but i think under load it will ping with the total so high. With what i have now i have 20 degrees advance. Ive messed with this countless times and can seem to get it just perfect. If the 12-32 works with out a ping a 6k ill leave it alone....my luck tho it wont happen.

With what you have above in timing i could prob use way more initial and way less advance, ill look into a different distributor or even if i can find an ignition box that i can adjust the curve. This thing with alot of initial has alot of snap but then too much advance and a ping along with it.



Edit: Ive found a kit to adjust the advance and just ordered it from summit, i should be able to limit it to about 16 degrees advance. Meaning i should be able to get my initial to 16 with 16 advance and 32 total...might just work out.

gottago
Posts: 205
Joined: Thu May 24, 2012 7:39 pm
Location: British Columbia Canada

Re: Dual x450's with model e's///pics fixed

Post by gottago »

I think that is worth a try fb. Those parts aren't likely that expensive and will let you know if you are on the right track or not. I've been schooled a few times about running the timing as high as I do but but some combinations just like it that way. The particular cam/ compression ratio/ and heads govern where timing needs to be. In the sbc I mentioned above the intake centerline is at 104 and it won't even idle properly below about 18 degrees initial advance. I locked out the timing at various degrees to find what timing it liked at different rpms. Then you have to set up a curve and deal with the limitations of whatever dizzy you have to work with. When running this high initial I have to run a much stiffer spring to keep the advance timing curve out til after 2000 rpm. Then I have to limit the total so all in before 3000. Even the hei is'nt real friendly and adaptable to making that sort of curve. Like you I played with timing a bunch before setling for best all round with parts that were available. I use msd stiffest springs modified a bit and hei weights trimmed a bit. I don't get any significant amount of advance till about 2200 rpm. This sbc runs very nicely at these settings no ping, no knock very smooth and responsive but I must mention that many others have gone on record saying this sort of advance is not the way to go. For what its worth fb imo running 16 initial with a slightly sltiffer spring is still plenty safe if the engine will take it. A good dial back timing light for initial setup and proper monitoring devices afterwards should tell you all you need to know. The engine will let you know what it wants. You've come a long ways from a year back..

flatblack
Posts: 225
Joined: Wed Jun 23, 2010 7:42 am

Re: Dual x450's with model e's///pics fixed

Post by flatblack »

Sorry i havent been back, messed my ankle up pretty bad, ill get to this asap. I wont be doing any wrenching for about 2-3 weeks. The mallory kit at least will limit my advance to 16 degrees, i should be able to set the initial from 12-16 to see what happens. My concern is heat and how the plugs look, im going to pull one and take a look then slowly crank it up. As long as there is no heat problems or ping ill leave it high. I have a 4hp starter lol so thats pretty beefy to crank it up.



edit, i ordered a cover for my balancer. It has all the timing marks on it so i can map the timing correctly with my timing light.

flatblack
Posts: 225
Joined: Wed Jun 23, 2010 7:42 am

Re: Dual x450's with model e's///pics fixed

Post by flatblack »

Ok ive fixed the hard starting problem with an impco sv connected to a momentary switch and the vac hose in the base plate, gives it a nice shot and fires up after only a few cranks. As for the timing i was able to get 16 degrees initial, 14 degrees advance and all in by 3200. That was the best i could do with what i have for the time being. I noticed tho at idle my afr when the trucks warm was in the 15s, i had a dead spot right off of idle. I richened the idle up on both carbs a hair to get me in the high to mid 13s, the dead spot seems to be gone....also made cold starts a little easier(should of known that). Although i have the idle at 825-850, its needed to stay running when its cold.



Oh, that adjustable advance kit was 40.00. I didnt use it yet, id like to see how it does with my current #s. I probably will be using the kit tho after this mud bog, im always looking to get more out of this small block. With the new trans brake, reverse manual valve body and a 2200 stall i should be able to crank it up and let go....if it works out that way anyway.

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