rufretic

iTrader: (37)

No graph yet but I'll have one soon, hopefully it will be a little easier to troubleshoot looking at the graph. Or maybe I'll get lucky and the spark plug wire was the issue and it will make the power it should this time.

qqwqeqwrqwqtq

No sense in speculating until it is back on the dyno without a burned plug wire.

I don't know when the wire cooked but I can tell you I couldn't feel or hear a misfire though I know it must have been.

Can't hear or feel much as far as a misfire when the car has no mufflers, an F2 and 4k converter.

IMO the cam and springs are fine (though the cam may not be ideal). Boost pressure from a supercharged car should not effect valvetrain stability. Backpressure from a turbo is another story.

Anyway, lets go through the motions on the intake valve.

Intake stroke- closed valve has 26psi of boost behind it and begins to open. Air begins to fill the cylinder and pressure between intake and cylinder begins to equalize.

valve starts closing and cylinder pressure/intake pressure should be rather close. As soon as the intake valve closes the Compression cycle starts and cylinder pressure immediately eclipses intake manifold pressure.

Power stroke, until exhaust blowdown. Cycle starts over at end of exhaust stroke during overlap.

Not really seeing any reason a supercharged engine needs more valvespring due to boost pressure, only that it extends the usable rpm range of the engine.

Anyway, I think the low numbers are due to the torque converter, which certainly isn't up to task, and the cooked wire. Will re-evaluate once I get it back on the rollers.

rufretic

iTrader: (37)

Thanks for clearing that up Jim. Can't wait to see how it does this time around. If it's still the same, I'll need to try a tighter converter. I might as well wait to do that until I have the fuel system to support it though.

98Camarod

iTrader: (43)

Maybe I missed it, but are you still running the ss4000?

Jim, at what point can you expect a converter to limit the performance? Specifically I'm asking for my setup.

rufretic

iTrader: (37)

Yeah, I just answered that on the last page but it's cool. Totally different set-up, this one is a th400 with a vig 4000. The old set-up I told you about was with the stock 346, D1, stock 4l60e and a ss4000. That combo worked very well other than it made too much power for the stock 346 to handle. Only lasted maybe 10 passes but they were all in the low tens and could have squeezed a 9 out of it but it blew before the finish line on the 10.1 pass. It trapped 138 so it deffinetly had a 9 in it. If my block wasn't so mangled I could have just kept that set-up and rebuilt the 346 to handle the boost and had a nice mild 9 second car. I had to take it to the next level and now I'm kinda regreting it Oh well, it might still turn out pretty nice but it sure took a lot more time and money than a nice mild set-up would have.

Haans249

iTrader: (24)

Well, if its not the springs, then definitely could be the burned hole haha. I must have missed the part of the burned wire. Sometimes you really can't even tell. I once accidentally left one of my wires completely off the plug and didn't even notice for a few mins while the motor was warming up at idle. No misfire, no stalling, nothing. I saw it, put it back on, and no change haha. Still ran fine.

But, 24 degrees of overlap, ~70 or so at 6thou lift is most likely a source of lost fuel. Probably would make a substantial more amount of power if there was a properly spec'ed cam for the setup!

Keep is posted!

rufretic

iTrader: (37)

You may be right about the cam eating more fuel but I don't think it hurts power on a blower set-up. Turbo, yes but that's a whole different animal. With my set-up, I wouldn't be surprized if a cam with less over lap made a little more boost but I obviously don't need that and I think the power would be about the same anyway. My 346 & D1 did better than most and it had a cam everyone said was too big also, 232/234 .598/.598 on 112lsa. It made 680rwhp and was performing even better at the track. I figured this new cam I spec'd would work close to that with the bigger 402 engine. That's why I chose it, just trying to use what worked before just on a bigger playing field.

rufretic

iTrader: (37)

It won't be able to get on the dyno until next Wednesday so for now I just have to wait. I'll post a vid later tonight of it running though so you guys can check it out but no street vids or dyno numbers until we put it back on the dyno and make sure the tune is good.

Haans249

iTrader: (24)

Your old cam would've been perfect. That cam has 9 degrees of overlap, MUCH less than the one you have now (at 23 degrees), and is the reason why it made good power on your blower setup, trapping most of the air and not bleeding it off out the exhaust. I wouldn't worry about making too much boost, thats what your boost controller is for. I would be more concerned with efficiency = power. Having FI allows you to run smaller/less overlap cams to make more power and have better driveability. The one you got now is a thumper, NA power making cam. Pull the charge pipe off and see what it makes NA, id bet it would make decent power (taking account the low compression). Anyway, take it with a grain of salt as I'm NOT an expert, its just from what I've observed. Good luck to ya!!!

rufretic

iTrader: (37)

I still have the old one actually. Might try it if it comes to that. I'm always interested to learn from others but, boost controller? I think you need to read what exactly I'm working with before you start making cam selection comments. This is a blower car, F2, not turbo. It boosts what it boosts unless I want to start swaping pulleys. Big difference in what turbos like and what blowers like. It's a pretty well known fact that blowers like a good n/a cam. This cam would make good n/a power, that's why I liked it. A good n/a cam may not make as much boost but they can still make great power.
Anyway, thanks for your input I just don't think it pertains to my set-up like it would a turbo.

helicoil

iTrader: (104)

Hmm.... What is going on during the blow down of the cylinder, before overlap? exhaust valve open, intake valve closed. 26 psi in the manifold is like 26 x Valve radius squared x 3.14 which equals effective psi working on the backside of valve, (basically trying to open the valve). If my math is correct that is another 85 pounds of pressure that is not there on a NA engine. Essentially, what this means is you need to subtract this value from your spring seat pressure, or compensate for it by setting it as the zero point when calculating closed valve spring pressures (seat pressure).

I thought this was pretty standard set-up for any blown motor??

qqwqeqwrqwqtq

When the exhaust cycle starts the intake valve has allready been closed through compression and power cycle and is stable. You would need enough boost to push the valve off the seat on it's own at that point, which isn't happening.

On a turbo engine exhaust backpressure is a problem as it can be double intake manifold pressure. Exhaust valve can bounce when closing as intake cycle is just beginning and there is not enough pressure in the cylinder to offset exhaust backpressure.

ChevyChad

iTrader: (50)

As long as the spring load is greater than the load of the boost on the valve, you should be ok. Seems to me that the force of the spring > force of the boost on the valve. Therefore, valve would remain closed by my math..

I hope ya get it figured out man

ninetres

iTrader: (35)

Like KP said. Get the car on a track. I made 700rwhp on one dyno, 615 on another (with a fuddle converter at that).......and then ran 140mph in a 3700lb car with a ballooning converter.

Dyno numbers are just numbers.

Haans249

iTrader: (24)

I still have much to learn about FI Great information in here!

rufretic

iTrader: (37)

Great info on the valve train guys, I love learning new stuff

Had to take the car home for a week since it's not going back on the dyno until Wednesday. It was an interesting drive home to say the least. First time driving with the new engine, first time driving it with the new blower, first time driving it with no power steering, first time driving strapped into a bucket and first time driving with a th400 ever. It was a little scary, hearing all kinds of weird noises I don't remember not to mention my head was ratteling from no cats or mufflers and I had to avoid cops any way possible. Luckly I had a short 10mile back roads drive and saw no cops and had no incidence and made it to the garage safely. It sure isn't much of a street car at this point lol. It will be a ton better when I have some mufflers on it. Plus it's not much fun to drive when your scared if you give it too much gas it might blow up lol. I krept home like a grandma Anyway, I thought I'd finally share a vid of it running so this is how it sounds:

98Camarod

iTrader: (43)

holy **** that blower is loud. Did you drive home without the hood? I'd be worried of sucking up birds and small children

rufretic

iTrader: (37)

Lol, no, I thought about it though but then figured the less attention the better. I need to get one of those turbo screens.

Oh yeah, about it being loud, you should of heard it on the dyno. I thought I could take it.....nope fingers went in the ears real quick. That sucker screams at wot!

rufretic

iTrader: (37)

I don't think I will sell it, at least I'm not trying very hard. If someone was to make me a good offer I might have to take it but I'm not planning on selling it now. It's just too exciting finally having it running again, I think I was just discouraged with the issues and I'm in need of money so it seemed like a smart thing to do lol. Worst case senario, I might just have to part out a few high dollar parts and then replace them when things get better.

helicoil

iTrader: (104)

I see and understand the concept on a turbo application......my thoughts were in relation to supercharged engines and the intake valve seat pressure 'rules of thumb' I and many other builders use. If boost is in the plenum (which it is - regardless of exhaust valve position) you have that force working against a closing intake valve (any closing intake valve for that matter), if you minus the pressure applied to the total surface area of the intake valve head from boost per the formula I listed above, the intake valve is not going to be in control when closing and can bounce of the seat leaking compression back into the intake (not good). This is the reason we run 300-400 psi of seat pressure on serious blown alcohol apps. in the 30-45psi neighborhood, ie. tractor pullers, all out drag, heads up engines, etc. 10-20 runs and the intake valve springs go to the exhaust valves and NEW springs get installed on the intake. It also explains the SFI mandate for blower restraints ......just trying to offer some input from my experiences.

I would assume many on this forum don't experience these issues on their procharged LS engines because not many are using serious superchargers like rufertic (sp?) creating 26 psi. It seems most pushing it are in the 18-20 psi range. I would suggest 200+psi of seat pressure springs minimum, maybe higher, can't have too much in my opinion. Of course, I don't think I would be using a HR cam either with that kind of seat pressure, most likely a SR. The final spring selection would be based upon how aggressive the closing ramp of the intake lobe is.

Good luck with the combo, I have been following along on and off for awhile, quite a bumpy road. I think it will haul the mail when it is lined out. Glad to hear you are making headway. Seems to have the interest of many 68,XXX views!!