Tom's B6 Build Thread

[sketchman]

Pedro pulls harder under partial throttle than full throttle. Partial throttle it always tries to maintain that 14.5 to 1 target.

Ya know. I could swear I felt that on my car too. Still stock ECU in yours? I thought I was crazy. I always roll on the throttle, and I just can't help thinking when I finally pin it it actually feels like it calms down a little.

[TominMO]

Do a run at 12.5, another at 13.5, then another at 12.5.

I could try to tune it to just go down to 13.5; maybe 42 or 43 psi. But I don't really see the point. I would rather just have the extra protection, as Charlie says, of having 12.5 at WOT. They typically do two pulls for their $90, so I'll do that for checking consistency.

[TominMO]

12.5 isn't for power, it's a buffer to protect the engine. Even highly tuned turbo engines run best (generally speaking) at 13.5 ish to 1. I ran an engine dyno test cell for 4 years, tuning everything from V12 jags, to Air cooled Porsche, to Robbie Gordons AM General Hummer engines for Paris to Dakar. Setting a modern engine to 12.5 to 1 is a precaution to cool the cumbustion chambers and reduce the chance of detonation in 80 percent of the modern engines I tested. If 12.5 to 1 nets you more power than 13.5 then your combustion chamber design is about as efficient as a Briggs and Struggle lawnmower engine.

Pedro pulls harder under partial throttle than full throttle. Partial throttle it always tries to maintain that 14.5 to 1 target.

It's interesting you say that. Take a look at my Matt D B3 dyno sheet here (post #153). Note how the bumps and troughs in the HP curve match pretty well with the more subtle changes in the AFR at the bottom.

So Charlie, what would meth injection do for my car? Any reason not to use it? How hard to install, and how would I tune the car differently? Is it good enough to just tune it by the wideband? Would I also need to change ignition timing?

[Advancedynamix]

Water meth is really difficult to get right on small n/a engines. This is mostly due to the fact that all the systems are designed for engines that make more tq. Even on Tweak my best results were with the smallest injector nozzle that snow performance sells, and I had to special order that. A little bit goes a long way with water meth. Theoretically, it would help your engine make consistent power, but in the real world it's not that simple.

That graph does show what I'm talking about. See how the engine pulls harder with the leaner ratios.
Also, if that is not a load bearing dyno jet then all that data has very little practical application. The burn rate, and fueling properties of an engine are heavily dependant on engine load. If the engine cannot be accurately loaded, then it can't be accurately tuned.
That would be like learning to surf in a stale swimming pool and comparing your performance to someone riding a wave.
That being said, a DynoJet without the eddy-current feature, would be better for tuning a stock festiva than a supercharged 5.0 mustang. The drum resistance more closely represents the load that a festiva engine encounters than a Mustang. The big problem is that the faster the drum rolls, the more the kinetic energy overcomes parasitic losses like tire friction and bearing drag. As those loads deminish, the unit becomes even less accurate at properly simulating load. An automobile sees greater load as it accelerates, not less load. Silly DynoJet.

[Advancedynamix]

Ya know. I could swear I felt that on my car too. Still stock ECU in yours? I thought I was crazy. I always roll on the throttle, and I just can't help thinking when I finally pin it it actually feels like it calms down a little.

Stock b6d capri ECM. The Capri management uses a real tps rather than the switches like the festy one. It's a little more accurate at precise tip in enrichment, but otherwise doesn't seem to be an advantage.
You are feeling the engine run richer at WOT, and you're not crazy, it's easy to feel. It's especially noticeable when climbing a hill and you roll off the throttle a bit and the car pulls harder. If you watch that on the wideband it's clear as day that the engine pulls harder at that 14.5 target. After all, 14.7 stoich is the ideal burn at sea level with gasoline, so it only makes sense that it also makes the best power in a perfect engine being driven in perfect conditions by perfect people wearing perfect shoes. Lol

[bhearts]

It's interesting you say that. Take a look at my Matt D B3 dyno sheet here (post #153). Note how the bumps and troughs in the HP curve match pretty well with the more subtle changes in the AFR at the bottom.

So Charlie, what would meth injection do for my car? Any reason not to use it? How hard to install, and how would I tune the car differently? Is it good enough to just tune it by the wideband? Would I also need to change ignition timing?

"They" make progressive controllers for water methanol injection that uses your vacuum signal to determine amount of methanol squirted. Better than on/off, but not perfect. Having a little water and methanol in your combustion would help you find that 14.5 ratio, and help you keep piece of mind, cause i know you don't wan blow it up. Don't want to enrich very much with methanol? Mix it more water heavy. 70/30.

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[Advancedynamix]

"They" make progressive controllers for water methanol injection that uses your vacuum signal to determine amount of methanol squirted. Better than on/off, but not perfect. Having a little water and methanol in your combustion would help you find that 14.5 ratio, and help you keep piece of mind, cause i know you don't wan blow it up. Don't want to enrich very much with methanol? Mix it more water heavy. 70/30.

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I run 50/50 mix, and wouldn't suggest a more diluted mixture for N/A because the IAT is much lower and vaporization will take longer. Also, the system I put on Tweak is a stage 2 Snow performance with a MAP controlled, adjustable progressive controller. The system was even a little tricky to tune for 181hp boosted dohc b6, because these systems were designed for 200+ ft.lb of TQ engines. It wouldn't work well for an N/A. There are a few ultra high end kits out there that use pulse width control electronic injection and could probably be tuned to work well on an N/A b6, but your looking at around 1000 dollars or more for the system. Even the stage 2 Snow kit is nearly 400 bucks. Megasquirt may be able to control an auxiliary injector for Water meth, but with all this complication your better off just mixing some e85 in with your fuel.

The water meth will richen your readings on the wideband. You typically can run leaner on your gas mixture when using Water Methanol injection because the water meth adds a little fuel and also supplies the safety factor of cooling the combustion chambers and resisting knock. Modern wide band control Fuel management systems automatically lean out when the water meth comes on because they see the rich condition and trim fuel. That is why a lot of modern turbo cars get increased fuel economy with water methanol injection. This doesn't hold true for pre obd2 systems though. There doesn't seem to be any added fuel economy on older cars.

[bhearts]

I run 50/50 mix, and wouldn't suggest a more diluted mixture for N/A because the IAT is much lower and vaporization will take longer. Also, the system I put on Tweak is a stage 2 Snow performance with a MAP controlled, adjustable progressive controller. The system was even a little tricky to tune for 181hp boosted dohc b6, because these systems were designed for 200+ ft.lb of TQ engines. It wouldn't work well for an N/A. There are a few ultra high end kits out there that use pulse width control electronic injection and could probably be tuned to work well on an N/A b6, but your looking at around 1000 dollars or more for the system. Even the stage 2 Snow kit is nearly 400 bucks. Megasquirt may be able to control an auxiliary injector for Water meth, but with all this complication your better off just mixing some e85 in with your fuel.

The water meth will richen your readings on the wideband. You typically can run leaner on your gas mixture when using Water Methanol injection because the water meth adds a little fuel and also supplies the safety factor of cooling the combustion chambers and resisting knock. Modern wide band control Fuel management systems automatically lean out when the water meth comes on because they see the rich condition and trim fuel. That is why a lot of modern turbo cars get increased fuel economy with water methanol injection. This doesn't hold true for pre obd2 systems though. There doesn't seem to be any added fuel economy on older cars.

Vacuum and rpm set points http://www.alcoholinjectionsystems.c...roducts_id=265

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[Advancedynamix]

That's a good start. Still going to be hard to jet for 100ft.lbs of TQ though. I've tried using mister system nozzles, but they don't flow enough and it just stalls the pump. Maybe someone makes a system for motorcycles without boost. That may be a good source. I haven't installed a system since the one I put on Tweak (4 years ago) so there are probably more options now. I still don't think the benefits are worth the hassle on a small, low compression, naturally aspirated engine.

[jdobbs86]

That's a good start. Still going to be hard to jet for 100ft.lbs of TQ though. I've tried using mister system nozzles, but they don't flow enough and it just stalls the pump. Maybe someone makes a system for motorcycles without boost. That may be a good source. I haven't installed a system since the one I put on Tweak (4 years ago) so there are probably more options now. I still don't think the benefits are worth the hassle on a small, low compression, naturally aspirated engine.

Not sure what the circuit on your meth injection looks like but it sounds like a add a return style fpr to the circuit might be a solution for tiny nozzles...at least that was my plan

[Advancedynamix]

That's a good idea. We should move this discussion to a dedicated water meth injection thread. That way it doesn't clutter up Tom's build thread.

[TominMO]

Dyno run scheduled for 2pm Friday.

[TominMO]

OK, dyno results are in, again. All of these are on the same dyno, which is a Dynojet inertia dyno.

Here is what it got back in Sept. on 40 psi of fuel. He didn't complete the test because he didn't like the too-lean condition at WOT. But you can get an idea of how it ran. Felt pretty peppy to me, out on the roads.


Here's what it got today on 50 psi of fuel. We tried 45, 50 and 60 psi, and 50 seemed to work best. Definitely a better torque curve, with HP staying the same. So I'd call this motor slightly more powerful than a B8. With a different cam, designed for higher HP numbers, of course it would have shown more impressive numbers; but I specified to Matt that I wanted a torquey, drivable car, and that's what he delivered. With a better intake and nice clean balanced injectors, maybe we'd be looking at another 10 HP?


And for comparison, here is what Matt's B3 did. The B3 had Matt's custom large-volume intake, whereas the B6 just has an unmodified stock intake.

[bhazard]

Too bad you can run a stock b6 for comparison but my guess is around 70 whp.

[TominMO]

Too bad you can't run a stock b6 for comparison but my guess is around 70 whp.

Right, I figure ~70-71.