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There's an error in those calculations. When you did the calculations "My way", you didn't divide the RPM by two (because air is only ingested on every second stroke). When you do this, the cfm you calculate becomes 1089/2 = 544.5 CFM which is within 1.5% of your answer. We can call it a...

Yes, the cams play a role in the harmonic waves, I never said they didn't. I said they're controlled by the intake plenum and runners though. At any rate, this has little to nothing to do with people tuning their street driven, modified, or even reasonably high performance vehicles. I'd...

You could always just jump 12V to the pump for a second to make sure the pump's OK (that would rule out a bad pump, or a bad relay). You could also test to see if you get 12V to the pump when you turn the key on.

Well, I can't put this any simpler than: 100% VE means a 3.0L engine uses 3.0L of air over a complete cycle (2 revolutions). If you run boost, you can get say 4.0L of air into a 3.0L engine, meaning you have a VE of 133.3%. That's the way it is, plain and simple. If you don't agree with...

If you want to be picky, that's correct, but the "theoretical air ingested" is usually the displacement of the engine (meaning 100% of the engine's volume). Since the theoretical displacement of the engine is 100%, if you were running boost, it would be much easier to be running higher than...

That's pretty much right on. Bigger (performance) cams generally need a bit more advance on the exhaust and a little more retard on the intake in order to cut the overlap down more. The bigger the cam profiles, the larger the inherent overlap. If you tune an engine for a certain set of cams...

Close to the TB is what makes sense to me for several reasons. The two biggest are: ONE and TWO It's hardest to get air through your intercooler since it's probably the biggest impedance in your intake system. If you put a BOV before the intercooler, when it goes off, the air in the...

I have this posted on *another forum*, but I wanted to share this with this community as well. I hope it's useful enough to maybe become a sticky as this seems to be a fairly frequently asked question. If anyone needs any help or would like some pointers that aren't available in this post...

On four stroke engines, it is important to realize that the cam rotates once for every two rotations of the crankshaft. Volumetric efficiency is based on cylinder fill. If a 2.0L engine is filled with 2.0L of an air/fuel mixture, we say its volumetric efficiency is 100%. If a 2.0L engine...

You CAN change pistons like that, and it will run. I ran into a problem on an engine and until I figured it out, I was going to keep blowing pistons, so I didn't want to fork out big cash until the problem was fixed. So, I grabbed a spare motor and every time I blew a piston, I'd just pop off...

Unfortunately, I just recycled my pile of 7M parts, rods included. I'm SURE there's someone out there with an engine torn down, or doing a build that would do this for you. You would probably get a better response from directly asking someone who you KNOW has an engine apart with a rod in...

I've had this argument with sooooo many people!! 10psi is 10psi, no matter what turbo you have AS LONG AS YOU SPECIFY AN RPM. If I make 14 psi on my DSM, but the turbo runs out of poop and has me back at 8 psi by redline, that's one thing. If I put a larger turbo on that still runs 14...

At 160k RPM, that's out of balance quite a bit and will cause it to wear out the bearings and seals until the turbine hits the housing, then you're really done. I've seen turbine wheels with less damage than that be out of balance enough to blow the turbo within a couple of weeks.

You're not actually trying to start the car with the boost checker attached, are you doing that? You're supposed to pressurize the system (with the engine off), and look for where air leaks out to see if you have a hole somewhere. If the air is rushing out your oil cap, then I'd guess that...

Some of you guys might know me from SF. For those who don't, a bit of background on me: I own an 88 turbo 5spd, that is getting major body work, a 1.5 JZ, and supporting mods to get me happily to the 600-800hp range. It's still in pieces, but as soon as it gets painted, I'll finally be...

I thought I'd throw in my $0.02 on this... The 2G DSMs had problems with their oil squirters getting stuck open because of crud in the oil. This causes them to get stuck open and since they share oil passages with the thrust washer, the thrust washer sees less oil, starves, wears through and...