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Inlet trumpet dyno testing


kpr
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well no major  gains.  I can say its horrible at part throttle.  didn't even attempt to tune part throttle, after seeing all the fuel hanging about.   At wide open it seems fine once it sucks up the fuel puddle and gets a few revs.  It gains a little power and seems to smooth out the power curve a bit. assume this is from the fuel mixing better once it has some airspeed.  also had to pull some fuel out up top. possibly better burn with less o2 left over?  for the same reason.      So yep need that staged sequential injection.  im too poor to spend that much for a few kw,  so back to normal now. 

also I had to shorten intake over normal setup. hence why looks bit janky inside

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I reckon it's one of those things where back with the old BTCC cars etc where it worked well, the injector spray patterns were probably super shit. 

Or injector control at low pulsewidth was awful so its more controllable to use two sets of smaller injectors than one set of big ones.

But modern injectors and ECU ability to control them accurately have probably come a long way.

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Jamie with the Ingear Starlet picked up decent gains going to outboards only and it idles & runs well with great throttle response (Atlantic 4AGE). Be interesting to see what fuel pressure and injectors he is running. I get the feeling for them to work well at lower airspeeds you need higher fuel pressure and a wide cone spray pattern on a modern injector for maximum atomisation. 

I can imagine them being a pain to tune as well, as injector timing will have to vary throughout the whole map depending on airspeed and reversion. 

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Most race class rules are one injector per cyl, they get the best power from outboards so that's there they go. As above there is lots to be done in the execution and the injectors spray pattern, pressure etc. I think some high end race classes were going super high pressure, to the point where classes have fuel pressure limits. I am not doing it myself so can't add much but it definitely makes good gains for NA if you invest the effort/moneys. I read that most of the gains are from the charge cooling rather than mixing, so maybe you need a hot manifold also? not sure. But I mean we have Glen who pops up on here who gained 9kw on his setup.

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1 hour ago, BobbyBreeze said:

Jamie with the Ingear Starlet picked up decent gains going to outboards only and it idles & runs well with great throttle response (Atlantic 4AGE). Be interesting to see what fuel pressure and injectors he is running. I get the feeling for them to work well at lower airspeeds you need higher fuel pressure and a wide cone spray pattern on a modern injector for maximum atomisation. 

I can imagine them being a pain to tune as well, as injector timing will have to vary throughout the whole map depending on airspeed and reversion. 

I'm not sure you can really say the engine idles well when you have an engine that idles at like 4000 rpm (no idea if this is actually the idle speed, but wouldn't be surprised).

 

Edit: Just looked at a youtube video, idles at like 1000 rpm. Not bad... Insanely rough idle though and really rattly

 

 

I've seen a video of a 3K-R and that thing would stutter and miss until over 5000 rpm

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1 hour ago, ajg193 said:

I'm not sure you can really say the engine idles well when you have an engine that idles at like 4000 rpm (no idea if this is actually the idle speed, but wouldn't be surprised).

 

Edit: Just looked at a youtube video, idles at like 1000 rpm. Not bad... Insanely rough idle though and really rattly

 

 

I've seen a video of a 3K-R and that thing would stutter and miss until over 5000 rpm

Just for everyone else following along.

Here's Jamie's engine on dyno.

 

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Mine idled just fine, no different to normal.  even though it looked like it shouldn't   guessing the closed throttle plate was kinda acting like a carb. 

Didn't seem to have any standoff issues.   in the first part of the below vid, it kinda looks like it does.   In the 2nd part with camera looking down, can see it firing some fuel back out on the rev limiter.    injectors are 980cc Bosch ev14 . have a pretty nice spray pattern once have a bit of duty cycle.  only running  stock fuel reg.  non referenced which i assume is 43psi.
intake never gets warm on normal setup.  with the outboards the ali section before the throttles had condensation on it whole time it was running

dyno runs where done within 30 mins of each other

 

 

dont share this vid anywhere.

 

 

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Was chatting to Markku about this. I reckon you need the hot hot intake manifold for it to work, and you likely get gains from cooling effect of state change increasing the air density giving you the power. Like if you have poor atomization its not hard to run slightly richer to ensure the oxygen is getting enough petrol.

BSFC improvements at WOT are important for a race car but doesnt matter for weekend warriors running a little richer.

But if its an air density thing, that begs the question of if youd just make that same power with an insulated intake and port injection? 

 

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Had a little play with the injector timing. didn't seem to do anything.  but didn't change it a huge amount.  unsure how much if any effect it would have if not having stand off issues. My end game is probably a lot different to  guys in the racecar world as well.  Ive messed around a lot getting the lower end of the power curve to work. which isn't really a priority on a 10,000rpm race engine.  Doing this is pretty much fixing the reversion issues, which will cause stand off.     Dunno maybe i just got lucky and my injectors were big enough to get all the fuel in, in the window of injector timing i tried  

Intake is pretty well insulated from the heat.  if look at pic at top of the page,  that black bit between head and throttles is acetal plastic. there is a thermal insulator gasket between that and head as well.  Then on the trumpet side of throttles is obviously insulated again with silicone joiner.


 

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im using 1000cc out boards and 650cc inboards both sets are running different end of injection timing and im at 75psi ,motor idles at 950 rpm out boards are dribbling on idle .my whole set up is blended in from idle up to 9200 rpm on the 2 litre .at 100 percent throttle its 95 percent out boards and 5 percent inboards .injectors are out board is a single pintle so cone type, and inboard is a similar to the 7mgte types

my inboards are from end of injection timing  185 to 95 up at 9200 the outboards are from 340 to 230 at 9200

 

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  • 2 weeks later...

I have nothing scientific to provide but I was at a 40th a couple weeks ago and got speaking to an older coach builder whose worked here, Aus and Eng. We got chatting about things and he mentioned your youtube channel, he was most impressed with your testing and set up. Thanks for giving us something to chat about.

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Question for you @kpr

You used to do a lot of road/track tuning with a few different techniques.

But now that youve had a dyno for ages.

Are there any areas which have given big surprises, as in, visible via dyno but very hard to quantify the old way? 

If you lost your dyno, what are the bits you couldnt do anymore, or what would you most miss.

Just from tuning perspective rather than excellent addition to videos.

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Other than not having to find a "closed road"  to do testing on.

most recent one was the outboard injection.   im sure ive told you about 500 times, I based most off my testing off afr change on alpha n tune.   with the outboard injection  I had a richer afr up top.  this would have sent me in the total wrong direction,  as would have assumed it lost power.   but was actually the same / slightly more power.

Kinda the same deal with the runner lengths.  the way the afr acted did not directly relate to the power.  but  did  give me the indication i was going in the right direction.  enough so that i have barley been able make any improvements on the intake made pre dyno.  having the  dyno opened my mind/ maybe just  confused me more  as to what is going on.

i can say some of the dyno testing you see is horseshit,  especially  looking at small changes.   its so easy to fire out different numbers changing nothing on the engine.  some times it can even be quite tricky just to get a repeatable number, especially on turbo stuff.       Ive lead myself into this trap a few times till figured it out..  add ignition advance  gain power, sweet add more, more power again  and so on.    then put timing back to where it was originally was,   hmm same power as when i had that big number in there.  turns out its just the temps playing games.  Ive seen some dyno tunes that seemed to have very aggressive timing numbers,  which i assume the tuner has fallen into said trap.   so yeah dyno  obviously  a good tool for ignition tuning but still can have its traps.

im sure there are lots of other things i cant think of right now.

 

And them numbers @Roman    numbers and graphs

 

 

 

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Regarding dyno tuning ignition timing, I found a somewhat similar situation.

I tuned each individual load/rpm cell for peak power/torque, was all good on the dyno

But on the road it was a bit rough as the power map wasn't even remotely smooth. I ended up just blending the timings in most areas to get a more smooth map, it made a huge difference

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Yeah I've been concentrating on that a bit lately, as it's easy to end up with a really jumpy sort of car. 

At the moment because I dont have IACV connected it's using closed loop ignition timing to pull the rpm down, so it sits at like 15deg ATDC to idle 

But as soon as you come out of idle mode by pushing throttle it goes straight to say 10deg so its a big jump.

Same as areas with a change in AFR goal, now I blend it out smoothly so you dont get weird shit if you're ever hovering just one side or other of a change from say 15.2:1 to 12.8:1 or whatever haha. 

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