DIY Fuel injection thread.

[Yowzer]

Yuh when the timing's too retarded the gasses are still expanding when the zorst valve opens, hence the rough sound. Also means less power coz it's flying out the back instead of into the piston. Chances are though, you'll be able to advance the timing beyond that of peak power before it starts knocking, especially with 98. But you'll be street dynoing it anyway so finding the right timing will be easy

[Roman]

Has anyone spent time playing around with injector timing?

 

Currently all of my injector timing has had end of injection set to 400 degrees before TDC

 

However I've just finally got my dual injector thingy all together and working last night. (Only briefly tested before laptop went flat)

 

Glenn (Celica RA45) has given me these settings for a beams motor running staged injection, for full throttle: (Note: this is start of injection timing, not end of)

 

I'm thinking that for cruising area of the map it'll still be best to stay at 400 degrees or so, so it vaporizes a lot fuel on back of the valves. 

At cold start maybe it makes sense to try spray directly in, rather than sitting around condensing on cold ports? Not sure if I can adjust for cold start though, maybe I'll just try set all of idle to a much lower timing and see how it goes.

[Testament]

I run the fiat in semi sequential mode with half of the fuel finishing injection just before IVO - not sure of the exact degrees though plus I think MS uses a different reference point. but same same really onto the hot valve before IVO.

[Roman]

After some previous mention in this thread about Virtual Dyno.

 

After some testing at Meremere, which is about as flat and straight surface as you're ever going to get compared to road tuning etc.

 

Unfortunately have to report that it's not so great. Fun for interest's sake but certainly not accurate enough to do any meaningful sort of tuning on.

 

All of these runs below were done with identical fuel, ignition timing, no wheel spin, etc etc and recorded at 100hz. Yet still showing a fair bit of variation there.

 

 

[mjrstar]

Any changes in wind, Iat, ect, tyre pressure, likely to affect results? Max variation was 25 ft lb and 16hp yes?

[Lith]

Really interesting amount of variation...  I think thats more than I got, maybe there could be the occasional outlier but it'd be easy to tell if it was a dodgy reading.   Decent power, though - how did the drags go?

 

Speaking of drags, the Torana with the Megasquirt I tuned a few months ago hit the strip a couple weekends ago and had a issues with a clutch not being up to it and being driven through but he did manage to get a 12.0 @ 118mph in the only run where it didn't COMPLETELY drive through the clutch, basically driving off the line.  Should be able to go mid/low 11s with a good launch and all the torque getting through the transmission methinks

[Roman]

^^That's with smoothing cranked right up, and having picked the best runs out of about a dozen. The rest looked worse.
 

It's gas money you could just spend hiring a dyno really

 

The drags were heaps of fun, my trap speed was 99.7mph (about 10kph faster than last time) so pointing towards some power gained compared to last time.

I just couldnt get the car off the line at all, my best quarter mile time was half a second slower than last time when I had standard ECU.

Reeled lots of people in towards the end, but lots of embarassingly awful launches.

I set an E-throttle map for first gear with reduced opening, tried launch control settings, and even went and topped up the gas tank completely full to try get some weight over the rear.

 

But nothing seemed to help.

[cute wee gem]

Did they have a prepped track last time, Roman?

[Roman]

It was raining in the morning this time, a lot of people I talked to said they were slower than the previous year at same event.

 

Neither time was a prepped track, but I think if you've had a week of dry weather and people laying down rubber, it's a different experience to when it's been raining that morning heh.
We ended up with all of the cars out on track back and forth to try dry it out:

Even my car which doesnt have very much power was wheel spinning in 2nd gear as well. I think my tires were near brand new last time though, and they've been heat cycled a shitload by now.

Some of the guys there with big power, just ended up doing skids down most of the length of the track hahaha.

However a lot of other cars were absolutely blitzing me off the start, it's the angle of the 4 links to diff that need changing in order to get a good launch.

[kpr]

10kph is a pretty sweet gain.  science wins this time, i lost 4kph somewhere.      you should be faster than me now with some more grip.  starlet ran 98.4mph 3 times in a row.  best was 14.1

[Roman]

Yeah the car definitely feels faster, so it was nice to have it backed up with some sort of non-Dave measurements heh.

 

Any changes in wind, Iat, ect, tyre pressure, likely to affect results? Max variation was 25 ft lb and 16hp yes?

 

Remember that when playing the NA game, you're battling for a single horsepower here and there haha.

 

so if the margin of error is 16hp, its not much help in tuning ignition or whatever where I'd be hoping to pick up 1-2hp max.

 

air temps would have increased through the day a bit though.

I guess some other factors are that I dont actually precisely know things like Coefficient of Drag for this car. If I had a more modern car where all of this is known, perhaps I'd have a better starting point for more accurate results.
I did fill up the gas tank at lunch time as well.

 

However, my issue with it isnt really that some lines are higher and lower. It's that the shape of the lines has changed completely between runs, some show 8000rpm dropping right off, other it stays flat. Some show a midrange bump, some dont. etc.

 

It's still a really cool idea though, and it's still within pretty damn accurate all taken into account! I would expect to have maybe 180hp atw currently.

[Celica RA45]

get the fucker dynoed you tight arse 

[tim13]

get the fucker dynoed you tight arse

you say that (and you are probably right) but how cool is what he has achieved with what he has available in both practical and i-t skill and some kiwi ingenuity ? higher trap speed says his method is working and no amount of dyno time would solve his traction issues anyway . also pretty rare and very cool for him to document both his successes an failures as honestly as he does (most dyno shops dont do that either)

disclaimer; I have never met Roman and personaly I prefer points , condensors and carbs

[Spencer]

Yes keep being a nerd, it's great.

[Rookie]

Lol, street cars dont need dyno work, you can easily achieve a safe 95% tune just by hooning around and using a scientific approach to your tuning method, not only that but it is fun.

Don't even get me started on some of the dodgy tunes that have come from reputable dyno shops, basically doing it yourself is better most of the time.

[Roman]

haha!
 

Dyno time is coming up, just need to arrange a time pretty much.

 

Will probably spend most of the time fine tuning my cruising area ignition timing and fuel for economy, ECU thug life

[Celica RA45]

just remember your motor is std so end of injection will be different to my race motor .so you will need to set yours up like how it came out of the factory tune it and then do the 2 stage 

[Roman]

There are a few more physical changes I want to make before it makes sense to head to the dyno.

 

I wanted to make sure that my intake was actually reducing the pressure drop at high rpm, datalogs from drag day etc proved that this is working well. As well as higher MPH over the line.

 

One problem though is that my new intake setup has the IAT sensor in a dead zone for airspeed, so its really awfully slow to respond. Previously as soon as you crack the throttle it would change readings, but now it's back to being pretty slow.

I might drill into the plenum just behind the TB and remount it there.

 

I also want to change over to an adjustable FPR so I can run it at higher pressure.

My main injectors are designed for 60psi, and that's what I'd want to run the staged ones at too.

 

Once these things are sorted I'll head to dyno.

[Roman]

Also one thing I noticed on drag day.

 

My outer fuel rail was getting frigging hot, like way hotter than the manifold its attached to.

 

Then I looked at the other fuel rail, which was also super hot.

 

I think the fuel is getting heated by the main rail, back to the tank then it's coming back really hot already. 

 

The main fuel rail is mounted on plastic riser blocks to insulate it from engine heat, but then the bolts run through the block and touch the metal rail, which is what I think is probably heating it up.

 

So I'll try add some insulating washers or whatever under the bolt heads and see if it helps keep the rail cooler. Maybe some heat wrap or something ziptied under the rail or something like that.

 

I'm thinking to get the most of the evaporative cooling effect you probably dont want your fuel to be 90 degrees to start with haha.

Hopefully wont need a fuel cooler setup because that seems like a pain in the balls.

[kyteler]

Plumbing a fuel cooler setup in wouldn't be complicated. Get heat exchanger, more line, plumb it in, the regulator and pump should do everything else.

http://www.summitracing.com/int/parts/flx-4136/overview/