335i upgrade and update

[EightySix Four]

Put in a set of Active Autowerke downpipes last week, and got to do some private road testing today with an automatic 2011 C6 Corvette. Runs from a stop up to about 45mph were severely traction limited on the stock tires and I was generally eaten up before the race got started. Rolling starts from 45mph or so is where things got fun. Due to the nature of a boosted engine on pump gas, the boost starts at 16psi or so after each shift and then tapers down to 12psi throughout the rest of the rev range. This was really noticeable on runs where we both got traction and launched hard; At the beginning of each gear, I'd begin to pull away, gain half a car length, and by the end we'd be near dead even again. This lasted all the way up to 125mph or so when we'd let off. Needless to say, I'm pretty happy with my big (for me) cushy sedan keeping up with a C6 so easily.

As soon as I get some more traction I'll be done messing with this car and see if I can get ahold of a track toy. I've moved away from the Corvette's for the moment and have a few other options on my mind, I'm in the process of launching a new company so I won't expect to make a purchase before December or so (which happens to be a great time of year on the pre-owned sports car market), but the serious test driving and shopping has definitely begun.

 

[PhoKingGuy]

And I thought my JB4 was enough....hmmmmmmmm

 

[EightySix Four]

And I thought my JB4 was enough....hmmmmmmmm

The JB4 on autotune with the downpipes is nice. I want to continue with the car because I like pushing it (big IC, meth) but I've decided enough is enough for a daily driver. Don't really need to make it to 500 wtq.

 

[halik]

Any hpfp issues?

 

[EightySix Four]

Any hpfp issues?

Not yet *knocks on wood*

 

[halik]

Not yet *knocks on wood*

So does chipping the car put more strain on the pump? Presumably higher boost means higher compression in the cylinder, so the pump has to work a bit harder?

 

[exdeath]

Always fun dragging Corvettes along. 😀 Especially when they get mad and won't look at you afterward.

 

[KentState]

So does chipping the car put more strain on the pump? Presumably higher boost means higher compression in the cylinder, so the pump has to work a bit harder?

Adding boost does not change the compression ratio of a cylinder. You are still taking a certain volume of air and fuel and compressing it the same amount. It may just be a bigger volume of the mixture.

 

[halik]

Adding boost does not change the compression ratio of a cylinder. You are still taking a certain volume of air and fuel and compressing it the same amount. It may just be a bigger volume of the mixture.

Err I meant the total pressure in the cylinder, presumably there's more squishing force going on with more input pressure.

 

[EightySix Four]

Err I meant the total pressure in the cylinder, presumably there's more squishing force going on with more input pressure.

Yeah, the pump is going to be working harder to get more fuel in, and it's going to be working against an increase in pressure (static compression with more air and fuel = more pressure), so I'm sure it'll fail at some point. Take chip out, take to BMW, get new pump, repeat 😛