19bonestock88's 2004 Saturn "Ion Green Line" build...

[cRiPpLe_rOoStEr]

Originally Posted by 19bonestock88

I still wanna use it at WOT though

Isn't it fitted with an electronic throttle plate? Can't you get a tune enabling the throttle plate to remain wide-open earlier and within a broader RPM band?

[19bonestock88]

The 03-04 Ions had a cable driven throttle, and simpler engine management than the later ones (no cam sensor, no MAF)

[cRiPpLe_rOoStEr]

Originally Posted by 19bonestock88

no cam sensor

Was its EFI still continuous-flow instead of sequential???

[19bonestock88]

Originally Posted by cRiPpLe_rOoStEr

Was its EFI still continuous-flow instead of sequential???

It has what was referred to as compression sense ignition, which uses ignition current to figure out which cylinder is firing and thus derive a cam position signal. Kinda neat.

[19bonestock88]

So, much of this build has been about the calm efficient “Dr. Jekyll”, and I wanted to showcase the “Mr. Hyde” portion too.

I changed wheel/tire setups temporarily for an event coming up at Tail of the Dragon, prioritizing lateral grip over efficiency. I had accumulated a set of 16x7” König Z-In which only weigh 15.5lb, and fitted a set of Firestone Firehawk Indy 500 tires in a 225/50-16. I lost around .75” of rolling diameter and gained 20mm in section width, likely over an inch of actual tread, these things are meaty. Given that I haven’t fitted the wheels with smooth covers I’ve caused some extra drag from that, and from the tire being wider. I also gained about 3lb per corner due to bigger wheels/wider tires.

That being said, the grip from these is incredible. I did lose around 12-15% on my highway mileage but on a twisty road there could potentially be mileage gains just from not having to slow down for corners. I feel now that I need a better seat and maybe a harness for holding me in place, but time will tell. Going back to my normal setup in a few weeks so my time of only getting ~40mpg highway is going to be short.

[freebeard]

....on a twisty road there could potentially be mileage gains just from not having to slow down for corners.

[me and my metro]

Looks good, maybe you won’t melt the brakes since the wheels can breathe. Have fun, stay safe friend!

[cRiPpLe_rOoStEr]

Originally Posted by 19bonestock88

It has what was referred to as compression sense ignition, which uses ignition current to figure out which cylinder is firing and thus derive a cam position signal. Kinda neat.

I knew about knock sensors, but I'm not sure to which extent they could actually measure the actual compression within a cylinder.

[19bonestock88]

Originally Posted by cRiPpLe_rOoStEr

I knew about knock sensors, but I'm not sure to which extent they could actually measure the actual compression within a cylinder.

It makes the calculations based on the resistance across the coil. Given that it’s waste spark there will be an obvious difference in amperage from the coil that’s firing on compression versus the one firing on exhaust, and the ICM looks for that difference to generate the cam signal which allows sequential fuel injection

[19bonestock88]

Originally Posted by me and my metro

Looks good, maybe you won’t melt the brakes since the wheels can breathe. Have fun, stay safe friend!

Brakes can breathe and there’s more grip so hopefully less need to brake