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| 250 WHP Supernatural 3.4 Build (Page 45/47) |
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La fiera
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JAN 27, 09:27 PM
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| quote | Originally posted by Blacktree:
And that's with a Rube Goldberg valvetrain. 
There's a guy on the 60degreeV6 forum revving his engine to 8000+ RPM in his race car. Look for username veekuusi. He also has a YouTube channel (also named veekuusi). |
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I've seen this guy's build but he screwd himself on the intake. Way too much plenum volumve vs runner lenght and width. He had too much area and too little lenght for that displacement, specially when he was allowed only -2 barrells per cylinders amount. He should've been in the 300-315WHP @ 8000rpms with that bore and stroke combo.[This message has been edited by La fiera (edited 01-28-2020).]
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La fiera
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FEB 13, 08:10 AM
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pmbrunelle
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FEB 13, 10:04 PM
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I think you used too much NOS:
https://youtu.be/pB-bN-RkJLM?t=52
The same weekend that I finished installing a MegaSquirt 2 in my previous 2.8 V6 Fiero (original stock engine), I drove 180 miles to the military base where I spent my Mondays-Fridays.
That Fiero saw full daily driver Monday-Friday duty right away, at the same time as I was building up my tune from scratch.
Driving the car in the morning following a cold start (lets say 50°F), there were a lot of pops and bangs for the first month or two until I started figuring things out. Nothing broke though... but your fabricated intake looks more delicate than the stock piece.[This message has been edited by pmbrunelle (edited 02-13-2020).]
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La fiera
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FEB 13, 10:34 PM
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I'll fix that problem with this part and also getting in the habit of having the throttle opened a bit at least at the first couple seconds of hitting the start button.
E85 also comes with its own oxygen so I believe that was also part of the problem.
The support from MS told me that that happens sometimes because when powering up the ECU it triggers the coils on re boot.
The problem is more pronounced since I now have DIS and E85, before with the distributor and gasoline it was less likely to happen.
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pmbrunelle
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FEB 13, 10:56 PM
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| quote | Originally posted by La fiera:
The support from MS told me that that happens sometimes because when powering up the ECU it triggers the coils on re boot.
The problem is more pronounced since I now have DIS and E85, before with the distributor and gasoline it was less likely to happen. |
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I know that with default settings, the fuel injectors give a priming pulse on key-on. This can be disabled if you wish by setting the priming pulse to zero.
I never heard that about the ignition coil(s). I'm going to check that on my car, with a spark plug outside of the engine where I can see it, and a friend turning the the key on/off.
If what you're saying is true, that's a serious flaw. If the engine is running at WOT while the CPU resets, then a spark could occur at a not-so-good part of the engine cycle, which could break things. I'm thinking of a scenario where a poor +12V power connection causes a power loss just long enough to trigger a CPU reset.[This message has been edited by pmbrunelle (edited 02-13-2020).]
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La fiera
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FEB 14, 09:07 AM
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| quote | Originally posted by pmbrunelle:
I know that with default settings, the fuel injectors give a priming pulse on key-on. This can be disabled if you wish by setting the priming pulse to zero.
I never heard that about the ignition coil(s). I'm going to check that on my car, with a spark plug outside of the engine where I can see it, and a friend turning the the key on/off.
If what you're saying is true, that's a serious flaw. If the engine is running at WOT while the CPU resets, then a spark could occur at a not-so-good part of the engine cycle, which could break things. I'm thinking of a scenario where a poor +12V power connection causes a power loss just long enough to trigger a CPU reset.
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You are absolutely right! But besides this mishap I've never had any other problems while the engine running.
But just to clarify the misfire happened when I hit the START botton, not when I re set the ECU. The ECU was already powered up and I took a while to start the car.
I will check the priming like you suggest. I don't remember if I have the priming off after the engine is warmed.[This message has been edited by La fiera (edited 02-14-2020).]
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lou_dias
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FEB 14, 03:09 PM
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I know you are trying to save weight but that does look like it's too thin...
As for a solution...just add a blow-off valve. 
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La fiera
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FEB 15, 06:43 PM
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| quote | Originally posted by lou_dias:
I know you are trying to save weight but that does look like it's too thin...
As for a solution...just add a blow-off valve. |
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You know, that was the first thing that came to my mind Lou!
I wanted to take the manifold out yesterday but wasn't feeling so well, It turns out I got type A Flu!
So I'll be out for a couple of days.
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pmbrunelle
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FEB 29, 11:55 PM
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I checked my car today for the supposed spark-on-boot behaviour, and I didn't see it.
I connected a spark plug to the coil wire, and I placed it such that it was visible from inside the cabin. I then cycled the key on-off (5 cycles). I did not observe any sparks. It was quite dark in the garage at the time.
I don't think we can generalise my results to all MS installs; each user should check this on his own setup.
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La fiera
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MAR 01, 12:12 AM
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| quote | Originally posted by pmbrunelle:
I checked my car today for the supposed spark-on-boot behaviour, and I didn't see it.
I connected a spark plug to the coil wire, and I placed it such that it was visible from inside the cabin. I then cycled the key on-off (5 cycles). I did not observe any sparks. It was quite dark in the garage at the time.
I don't think we can generalise my results to all MS installs; each user should check this on his own setup. |
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I was thinking; my injectors are high up in the runners and E85 has its own oxygen and that makes a big problem.
All it takes is to have some residual fuel in the runners and an intake valve open.
In my case, I hit the start button, the spark plug fire (waste spark) and the residual fuel in the runners ignited. Having the TB closed and the explosion expanding without a way out,
the manifold weld gave out due to the energy of the explosion. I never had this problem with non-oxygenated fuels, I switched to E85 I started backfires here and there, but this one was severe.
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