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Re: MPI Manifold for my 340?
[Re: Mopar_Rich]
#222468
02/15/09 09:46 PM
02/15/09 09:46 PM
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Anonymous
Unregistered
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Anonymous
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Are you doing the sweep over the full rpm (idle to redline) range? I assume at WOT. How about part throttle conditions? To simulate cruise you would have to be pulling only 10-20 horsepower on the dyno, I would think.
Is the 5% for AF or EGT, or both? Plus and minus or total high to low?
I find the numbers to be interesting and can give some insight into what I have found, % wise.
When I was running the last engine (bigger open chamber heads, more cam) the difference I would see in the onset of lean miss at cruise with different manifolds would be about 1/2 point of AF. It was right in the range of 14.4 to 13.9 which is within 5%. I would have to richen up everything to get the leanest cylinder to quit missing. Unfortunatel, I don't know what the actual mismatch was. From reading the plugs, I could tell which cylinders were going lean, as there was enough difference to show on the plugs. I did a bunch of testing by balancing the flow to get even distribution (epoxy and popsicle stick style) and could get a bad manifold to have even distribution and run at the .5 AF higher, but when I did the other tests at different rpm and load, it would be off again. The good manifolds didn't exibit a change between the tests and ran well at the high end of 14.4 AF at cruise and 12.5 under boost. With the worst of the manifolds, I would have to turn on the water injection 2 psi sooner to prevent detonation at 12.5 AF. If I took it to 12.0 I got the 2 psi back. The good manifolds were OK at 12.5.
The current engine on the 302 heads, Performer, lots of quench is extremely resistent to detonation and lean miss, and I think the higher velocity in the runners also helps. I will go down the highway at 60 mph, 2100 rpm, manual trans at up to 17 AF. Granted, the throttle is a bit soft at that setting, but it doesn't miss. It also doesn't show a change in egt compared to running 15, so I appear to get full burn at both settings. Fuel consumption is essentially identical also. Under boost, this engine will go at least 2 psi higher than the old engine without detonation, even though the compression is higher.
I understand that my goal of very good efficiency and lots of brute force are different than most of the coversions done. The turbos allow me to run a combination capable of much higher efficiency, and leaner mixtures than most hipo engines. If a person is dealing with an engine that has a bunch of cam, big heads, set up to go 6500+ rpm, etc, and on an automatic, it is not going to run really lean anyway, so if you have .7 AF (5% difference) between cylinders, you probably wouldn't even feel it, or see it on the plugs.
Your tuning at the torqe peak is a good one, as it is near the middle of the useful WOT rpm and also where you are likely to do damage from mixture issues. It also makes sense that you would see error there, as the combo has a natural sweat spot based on cam, heads, and intake design. If a runner is different than the others, it will have a different sweet spot and underperform compared to majority.
Just one more question. Have you ever run that same sweep on a matched runner OEM engine to see how well they match? That would be very interesting information!
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Re: MPI Manifold for my 340?
#222469
02/16/09 12:21 AM
02/16/09 12:21 AM
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Joined: Jan 2003
Posts: 1,938
Sonora CA
Mopar_Rich
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,938
Sonora CA
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Quote:
Are you doing the sweep over the full rpm (idle to redline) range? I assume at WOT. How about part throttle conditions? To simulate cruise you would have to be pulling only 10-20 horsepower on the dyno, I would think.
I run from idle to a safe RPM usually just past torque peak. I do it by having the dyno hold the RPM (500 RPM increments) and sweep the throttle from idle to WOT (if the dyno can hold it). That way I pretty much cover the entire "safe" range, NOT just WOT.
Quote:
I would have to richen up everything to get the leanest cylinder to quit missing. Unfortunatel, I don't know what the actual mismatch was. From reading the plugs, I could tell which cylinders were going lean, as there was enough difference to show on the plugs.
I would first use the EGT as an indicator. But after adjusting EGTs, by adjusting individual cylinder fuel, I switch to cylinder timing adjustments. Advancing the timing leans out a cylinder to a much finer precision than changing the injector pulse width - and I'm able to do timing changes as a function of RPM which I cannot do with the fuel.
Maybe I'm not a good plug reader but at this point I'm not able to see changes by reading the plugs.
I have only done this with normally aspirated engines, never forced induction.
Quote:
Your tuning at the torqe peak is a good one, as it is near the middle of the useful WOT rpm and also where you are likely to do damage from mixture issues. It also makes sense that you would see error there, as the combo has a natural sweat spot based on cam, heads, and intake design. If a runner is different than the others, it will have a different sweet spot and underperform compared to majority.
That is exactly what I have found out to be true.
Quote:
Just one more question. Have you ever run that same sweep on a matched runner OEM engine to see how well they match? That would be very interesting information!
Sort of. I've done this testing using dual-plane stock type manifolds to pro-stock sheet metal manifolds. The last sheet metal manifold I looked at needed no adjustments at all - but virtually every other manifold could have been improved if I was willing to spend the time doing the tuning.
You Also asked:
Quote:
Is the 5% for AF or EGT, or both? Plus and minus or total high to low?
Good question! I guess it depends. I felt if I could get +/- .03 A/F ratio with less than 5 degrees of timing adjustments I was happy. But sometimes I could never get there. I also could never predict what the engines ideal A/F ratio would be at a particular load/RPM/vacuum point. So once (sorry I only did this once} - I first zeroed out the map as best I could. Then I data logged the TORQUE at all the test points - about 5 for each 500 RPM increase. Then I went back to each point statically, and changed both the overall A/F (via VE) and ignition timing looking for maximum torque. What I found out - Engines like to run lean as long as they don't misfire or ping. DUH! I quit for the day and went out and had a beer.
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Re: MPI Manifold for my 340?
[Re: Flo]
#222470
02/16/09 09:50 AM
02/16/09 09:50 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
I would like to jump in here if that is OK and add my question.
It seems like I have a somewhat similar setup: 344 with ported 302s with 2.02 valves. At the moment I have an Eddy Performer and a 600 carb. Still dialing it in on the dyno... I will have that motor on the dyno for the next two to three months and a lot of time to play around with it and work out the bugs.
I already have a distributorless ignition and want to go Megasquirt next. This motor must have some lowend-torque as it will go in my 67 Fury. Stripper car (no options except AC), nevertheless not superlight. Cam is Comp 264HR with 1.6 roller rockers, I may be Ok with going one step hotter. A500-trans (low first) with 3.23 gears (cannot go deeper... Germany... Autobahn...).
The only EFI-manifold I see is the Edelbrock 28155. This is a Super Victor thing, which seems totally off for my motor. I do not want too loose of a converter in my mainly street driven car, so I would like torque starting somewhat at 1500rpm latest. My stock hydraulic roller lifters will be done at 6000rpm, if there is a useful option I would upgrade, but it stays hydraulic roller. Is there a manifold out there with injector bungs for my application?
If it was carbed I would think the air gap is the way to go from what I read. Is converting an airgap to EFI a good idea?
Anyone having some real world experience?
Thanks
Flo
PS: reading Rich' articles... and his cookie recipe :-) hmmmm.... :-)
flo- if you're looking to maximize idle-5000 RPM performance and torque, you might want to think about swapping over to a magnum style head and running a stock magnum intake (the "beer barrel"). they're a very long runner manifold and are awesome torque producers.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: MPI Manifold for my 340?
[Re: patrick]
#222471
02/16/09 11:02 AM
02/16/09 11:02 AM
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Joined: Sep 2005
Posts: 401
Berlin, Germany
Flo
mopar
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mopar
Joined: Sep 2005
Posts: 401
Berlin, Germany
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well, changing heads is out of question for now. Spent some effort and money in the 302s.
But one of these stock intakes might be interesting to try for comparison as I expect them to be fairly cheap.
Last edited by Flo; 02/16/09 11:29 AM.
1967 Fury III 4door HT
tiny 318, late model roller block, bored and stroked to 344
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Re: MPI Manifold for my 340?
[Re: Rug_Trucker]
#222473
02/16/09 12:06 PM
02/16/09 12:06 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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"I would first use the EGT as an indicator. But after adjusting EGTs, by adjusting individual cylinder fuel, I switch to cylinder timing adjustments. Advancing the timing leans out a cylinder to a much finer precision than changing the injector pulse width - and I'm able to do timing changes as a function of RPM which I cannot do with the fuel."
Rich,
I am having some problem understanding how this works. How does advancing the timing make it go leaner. What happens to egt when you do it?
Are you reading your AF with O2 sensors, or do you have gas analyzer also?
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Re: MPI Manifold for my 340?
[Re: Clair_Davis]
#222474
02/16/09 01:57 PM
02/16/09 01:57 PM
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Joined: Mar 2005
Posts: 168
Central New York
DropTopE
OP
member
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OP
member
Joined: Mar 2005
Posts: 168
Central New York
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Quote:
FWIW, you CAN modify the Magnum intake to work with an LA, and you don't have to grind down the vertical shoulders to do it. You DO have some grinding to do, but you can do it in a way that you'll end up with an intake that will work on both types of heads:
IMHO, if you haven't already got a good set of heads (or domed pistons), you may want to take this opportunity to upgrade to some Magnum-style heads. That'll give you a bump in compression, better ports, and no need to modify the manifold...
Clair
WOW - my thread really got some great technical action over the weekend. I have been trying to absorb all the differences and understand the impact to my situation. Thanks for all the input on this guys !
I will likely use the Magnum manfiold that is modified to work with LA heads. My present set up is the small chamber version aluminum edelbrock head with stage 3 porting so I will be retaining the LA heads. I have tons to learn about here and most of my questions are so far down on the learning curve they are not being hit in this thread. I have made some initial contact with Rich and will be following up with him on this quickly.
Thanks again !
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Re: MPI Manifold for my 340?
[Re: DropTopE]
#222475
02/23/09 12:09 PM
02/23/09 12:09 PM
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Joined: Sep 2005
Posts: 401
Berlin, Germany
Flo
mopar
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mopar
Joined: Sep 2005
Posts: 401
Berlin, Germany
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well, I am still not sure what manifolds to buy/try.
I totally agree with the idea of even air distribution. But actually a properly done single plane should be better in achieving this than a dual plane!
I will have some dyno time so I like to try several of these manifolds, but I do not want to sink endless money in buying manifolds I dont need.
-I think I will definitely get an Air gap or the knock off version.
-I already have a regular performer.
-I am considering getting an old Edel Streetmaster. Actually the idea of a small single plane makes sense to me. They are cheap on Ebay and I am curious how they do.
-Also I would like to try a modern single plane. There are so many MP part nos out there and I cannot find a good explanation for them:
P4876334
P5249614
P5007380
P4876334
Anyone tested any of these and has some results.
-There is still the Torker II, is that thing too large for a street motor which is done at 6000rpm? Anyone tried one with EFI?
Regards
Florian
1967 Fury III 4door HT
tiny 318, late model roller block, bored and stroked to 344
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But what I do, is I sweep the RPM range, data logging the mismatch. Then I zero out the worst RPM/load point. Then I make a few pulls to see how far out the rest of the map is. It's usually within 5% because the largest mismatch is usually close to torque peak. If it's within 5% I call it a day. 
