beaterX project thread - Page 47

95talonracer · 06-08-2011

When were you dynoing?

**Murlo26** · 06-09-2011

Wow, looking great Scheides! Can't wait to see it fully tuned up

**scheides** · 06-09-2011

Weds.

Matt D. · 06-09-2011

Looks great! I forget, is this logging a wideband or narrowband O2?

**scheides** · 06-09-2011

Narrowband, LOL yea right!

Wideband fo sho.

To be clear, the boost just happened to go this high, my goal is to keep it right around 30. It was a good test of the fuel system though, so I am happy with it.

Matt D. · 06-09-2011

Quote:

Originally Posted by scheides

To be clear, the boost just happened to go this high, my goal is to keep it right around 30. It was a good test of the fuel system though, so I am happy with it.

Just happened to go that high... Yeah, right!

Are you worried about the stock wiring being the weak point with such a large fuse in there now?

**Murlo26** · 06-09-2011

That is the idea of many fuses, to protect wiring, not protect devices. Basically anti fire device

**Kracka** · 06-09-2011

Quote:

Originally Posted by Murlo26

Basically anti fire device

Yes, but only if they're properly sized for the gauge of wire they're being used on. Going from a 20A to a 30A doesn't sound like that big of an increase, but it's still 50%.

**Murlo26** · 06-09-2011

Well what gauge wire is the fuse on? 14 awg maybe? 14 is good for 15 amps, 12 awg for 20 amps...and so on.

I am an electrical engineer, done plenty of fuse sizing in my day.

**Kracka** · 06-09-2011

So say it is 12 awg since the factory fuse was 20A, wouldn't running a 30A fuse on it become a fire hazard?

**Murlo26** · 06-09-2011

Possibly yes, depending on the wire rating. Some are rated for higher temperatures. What I quoted was the 75 degree C wire rating. There is also 60 degree and 90 degree and really high temp stuff that you can get away with a lot more.

75c is the norm typically though at least for industrial use, I am guessing auto is similar.

It honestly all depends on what kind of current he is actually drawing. If I knew that it would be easy to tell you. And it also depends on the type of fuse. There is an entire icky thing called fuseology...basically you have fuse curves that depending on current levels and length of time at those levels the fuse will be fine or blow. It gets messy.

**scheides** · 06-09-2011

Yea I would put in a 25A fuse but all I had was 30. I don't expect it to be a fire hazard as it's not going to continually run at the full 30a. The kit itself includes an upgraded 40a fuse so anyone that has installed one has likely run into this same problem.

If it ever is a problem, I make sure to carry a fire extinguisher at all times in the trunk.

**Murlo26** · 06-09-2011

^I am going to start carrying one myself. I think it makes sense with the level of modification I have.

**scheides** · 06-09-2011

FWIW I had done probably 10+ pulls w/o blowing the stock fuse so I'm guessing it's running right around 20A. The weird thing is that it blew right as I was getting on it, not like at the top of 4th gear or something (after a looooong pull at high amperage).

**Kracka** · 06-09-2011

Probably due to a quick spike as it turned on I bet. Like turning on a light, the initial surge is always greater than constant draw.

**Murlo26** · 06-09-2011

Correct, the pump is an inductive electrical load and will have a high inrush current. If that inrush is high enough the fuse will do its job and blow.

This is part of the same fuse curve I was talking about. Say a 20 amp fuse hits 30amps it will blow instantly, but at 21 amps it will probably take 5-10 seconds depending on the fuse.

You can blow 20a or 30a fuses very easily with a lot less running amps. Meaning your actually running amps could be 12-13 amps only.

Inrush is typically 10-12 times the amount of your actually running amps.

**Murlo26** · 06-09-2011

Also remember current equals heat and heats up the wires and then resistance goes up and creates more heat. So sustained use makes it easier for fuses to blow as everything is up to temperature.

**scheides** · 06-09-2011

All good points, thx guys

**Murlo26** · 06-16-2011

Updates!

**scheides** · 06-16-2011

Update with dyno numbers!

First off, BAP is working like a champ. To clarify, it shipped with a properly-sized 30A fuse for the stock fuel wiring.

Next up, the Cobb BOV. This thing is smoother than a crushed stock BOV but is it really holding boost? I had been suspicious so I swapped my stocker back on just before I hit the dyno. AFR dropped nearly a full point on the street--this tells me the stocker is leaking. So I just left it on and after shane did a few warm-up baseline pulls I swapped the Cobb BOV back in with ZERO other changes:

So basically as it had been on the street (self-tune with some GREAT guidance from shane@DB) on the cobb valve it rolled in on ~460whp. Holy crap! I was so excited I couldn't believe it!

Shane made some changes to fueling to help address a part-throttle issue I had been having around 2500-3000 and tweaked timing slightly and that was about it.

Boost is about where I had it on the street with my hybrid MBC/BCS setup, the turbo is about at its limit from 6500+ as WGDC is pegged at 100%. I'm not trying to get a ton more out of it for now, this will be my every day tune as well as my drag/autoX tune. The car responds very linearly and the powerband is just wiiiiide and strong.

I'm very happy and I have some video that I'll post later.