333pg333

How large is the TB Sid?

blown 944

Pay, I forget the exact size. I did a thread on it awhile ago. It's off a BMW 535i. Late 80s iirc. Pretty easy mod

DDP

Ah ok. Still great numbers Sid. I'm just curious why you discount the dyno so quickly. Personally, I like them because that's what I'm used to. Originally you thought your car was putting down a true 550whp due to the trap speeds. I can't discount your argument because I do trust what you're saying and I've heard it before. I just really prefer dynos because I'm not big into drag racing. If you put down 522 whp on a dynojet that equates to about 481 whp on a dynojet (8% difference). As far as I'm concerned, a mustang dyno/dyno dynamics read the most accurate. That would put your 550whp estimate high by about 70 hp...in my opinion. I don't mean to continue in circles arguing. I feel as though on the strip there are more variables that aren't under your control than there would be on a dyno. I'm just trying to understand why you feel so adamantly that trap speed is most accurate. Either way, great numbers for your altitude! Great numbers for any altitude really.

spoolin51

Group hug anyone ?

blown 944

Derick, the reality is that I've just seen so many fall short of what the dyno said that I prefer using a true measurement. Hell we could go rounds regarding accelerometers vs load dynos. Until you actually get a measurement from point a to point b you could continue arguing. Then there are correction factors etc.

In regards to 520 vs 550. Well, like I said, and I'm making no excuses here. I ran it on the dyno at lower boost levels than my last times at the track. I just didn't have enough runs to creep up on it. Like josh said, and I bow to his expertise, my IDC and MAF voltage were not the same as what I saw. The reason I know this is because I was worried about running out of injectors yet again after the last track outing, whereas on the dyno I had plenty of room.

I'll still stand behind the idea of using a true race to judge a cars potential over a measurement machine.

It looks like you have W's car making great power. Go drag it and see what trap speed you get.... Yes there are variables, but regardless I've been able to run over 125 consistently whether it hooks or spins, whether I bog or spin or do a granny take off. At this point, I'm the only one doing this. When I see other high number cars doing it or I can do a direct roll on against them I'll not change my views.

I've just been doing this long enough to know that I've seen too much "dyno bragging" to take it very seriously.

I only believe in them for a direct comparison... On the exact same dyno with the same conditions.

Too easy to fool in other words. Trap speeds never lie....

blown 944

Also Derick, if I gave you the fully corrected numbers.... Well you'd quickly see what I meant..

Rogue_Ant

You could argue that a mustang/dynamics dyno is more conservative, but arguing that they are more accurate? I don't think so. A Dynojet is a static mass, you accelerate the mass. F=M*A, doesn't get much more reliable than that. Any other type of dynometer, eddie-current, water-brake, ect, is having to derive force from a much more indirect measurement.

Also, that is why Sid likes the drag-strip for true power measurements. Who cares if your dyno reads 1000hp, if you only do a 110mph trap, then the dyno reading was complete BS. What matters here is how fast does your car accelerate? Can't trick that measurement, which is, again, force = mass * acceleration.

95ONE

I can only say that I completely understand what SID is saying about Dyno bragging at the track. Its funny at first and then just not funny at all after the unteenmillionth time someone tells you their ridiculous dyno number and runs like a turd. Just too much of that. Then there's the guys who worked all night long to get their car up there and forgot to check about 10 things and never even checked to see if the damn thing worked before they put it on the trailer. They get there and tell you how quick it SHOULD be and and how awesome the parts are (That they just threw on there without knowing how they match up with whats on there already) They always break down. Burn up a clutch. Make it half way down the track for one reason or another. Tiresome.

THEN... there are the real sneaky bastards who run 3 stages of power. Lowest all night until someone bites on a bet... Two ends of the yardstick.

Yeah, I was a 1/4 mile junky for a while. It has it's moments.

333pg333

I'm still inclined to think that a GPS measured roll from say 100kmh-200kmh can at least eliminate some of the variables. Not sure if that might have a more forgiving effect on a heavier car than from a standing start? Sid, what formula do you use for your 1/4 whp calcs? Dyno's also have way too many variables available. When they did my last ones they did a last pull and manipulated the reading by changing the ramp rates and also re positioning the car on the dyno. This gave something like a 25whp bonus 5 mins after previous pull. They also said where you put the sensor to read underhood temps makes a big difference.

blown 944

Patrick, I keep an old Moroso power speed calculator close by. It has served me well over the years. It looks like an antique now lol. I add about 10% to it for these cars because you lose some speed off the line. Pretty dead on from engine dyno minus drivetrain loss back when I used to do such things.

Duke

I haven't read the whole thread but I just say go for it!! Looking forward to your results. Even if you hit 650 or something else it will be great. Just make sure you document it well and get VIDEO when you drive it

blown 944

Yeah yeah... Hey I got some video at over 500.. Crappy video but ... Lol.

evil 944t

I like Patricks thoughts. A g-box and 60-130mph is a good test. It removes a lot of doubts. Unless you can spin your tires starting in third(or 4th) at 60mph. This is not a dig on you Sid, just another thought on how to measure things. I hope you hit your goal. Give me a call if you wanna chat..

blown 944

I agree. That may be the most accurate. However, you still have some variables like shift, road grade etc.

What these cars really need is a 1/2 mile timed and measured event. Then you'd be over all variables.

toddk911

MAF v seems to be fairly accurate assuming you do not have major diameter changes right before/after the housing.