|
| Hyena |
|
|||
|
I had my car dyno'd yesterday and during the course of sorting out problems we disconnected the BBM vacuum line to compare differences.
I hadn't actually seen a dyno chart of this before so I thought I'd post it up for others to see the difference between running long and short runners 
(ignore the peak power, that needs to be looked at too!)
_________________
Last edited by Hyena on Thu Feb 17, 2005 12:27 pm, edited 1 time in total. |
|||
| Top | |
|||
| 4.9 EF Futura |
|
|||
|
So i assume the red line is without the switching manifold? i.e. short runners for the entire run. Damn, look at the kink in that blue line! Still comes out on top of the red up until 120kw tho.
You're expecting a higher peak? I would have thought 145kw to be a fairly good result. Looks like a fairly typical 6cyl n/a power curve. I'd be stoked with your air/fuel ratios - look pretty much spot on!!!
_________________ I promise..... I will never die. |
|||
| Top | |
|||
| drazull |
|
||
|
Nice result. I wish I had 145 rwkw.
_________________ Not lost any demerit points |
||
| Top | |
||
| uglybob |
|
|||
|
hmmm.. johno should post his dyno up - he had major issues with the short/long runners kicking in on his EL XR6 - hence why his dyno reading was about 15-20rwhp below what he expected...
_________________ R.I.P. Scotty |
|||
| Top | |
|||
| Hyena |
|
|||
|
Yeah, 145 isn't bad, but it's supposed to be 170. That's a little more than what you'd expect from dyno to dyno so it needs investigation. The thing is though, the peak power shouldn't be affected by this so I don't know where/why it's reading low. As I said in the drags thread, I had 136 rwkw before with just a wade cam so there's no way this is only 9kw more with the bigger cam, bigger valves, bigger bore, much higher compression, head porting, etc etc.
Ugly bob, do you know what Johno ended up doing to fix it ? Was it just sticky or what ? I too have that problem as per this chart below. It definitely accounts for the flat spots I've been getting! It's intermittant too, does it sometimes but not other. The dyno guy thought it may be because of the big cam there's not enough vacuum to activate the change over smoothly/quickly/properly 
Red is with the vacuum line disconnected, blue is a 'normal' run. You can see even on a "good" run the power is less than what it should be from ~3900 - 4300rpm compared with just the short runners alone. Comparing the 2 charts I need it to switch in promptly at 3300rpm. It looks like it's slowly dragging out the changeover until 4300rpm... 
_________________
|
|||
| Top | |
|||
| uglybob |
|
|||
|
johno has an EMS 8860 - so i'm pretty sure he could adjust it from there... but hes getting twin TB's this or next week anyways, so it won't be an issue!
but i'll get him to jump on here, and give his input - a lot more insightful than mine ever will be! 
_________________ R.I.P. Scotty |
|||
| Top | |
|||
| neil101 |
|
||
|
Whats the guy that built your engine say?
Have you show him the dyno graph he may be able to shine light to the problem. Neil
_________________ HSV I JUST BEAT ONE !
|
||
| Top | |
||
| neil101 |
|
||
|
I'd post my dyno sheet up if I could get it to work (anyone able to help with that) so then you could get an idea of the bbm curve.
Neil[/img]
_________________ HSV I JUST BEAT ONE !
|
||
| Top | |
||
| skootin |
|
||
|
Have you tried to ziptie it fully open I have done some trial and error with the vac adjustment you really need a generous dyno operator
|
||
| Top | |
||
| Hyena |
|
|||
|
The dyno guy was happy to play with it, I ended up doing about 10 runs. First time around it capped at about 4700 rpm and I we were both thinking wtf ?! when I realised it was in 4th gear and the computer was limiting to 180. So back to 3rd gear and off we went. We started playing with settings (thats when we removed the BBM vacuum hose) but I was in a hurry to get to the drags and was running really late as it was. They ended up selling out early so I didnt get to run anyway so I should have stayed and fiddled with it
_________________
|
|||
| Top | |
|||
| justfordima |
|
|||
|
no, you shouldve left earlier, and played with it later, another day.. I really wanted to see you run...
Cheers
_________________ ;++JustForDimSim++;
|
|||
| Top | |
|||
| Hyena |
|
|||
|
Yeah, but if it's playing up I would have run a crap time. That said, I'm still spewing about missing out as I was still going to run, confident I'd beat my previous 14.8 (wade cam + extractors) I guess when I do return I'll be doing it with full power behind me and do it properly
_________________
|
|||
| Top | |
|||
| Disco Frank |
|
|||
|
johnnos car had a kick and a jump in power when the broadband switched over but a lower peak power figure...u can actually feel the change in the car
by leaving it with the long runners peak power went back up weierd...
_________________ RIP SCOTT |
|||
| Top | |
|||
| USELESS |
|
||
|
I have the same power loss /kink in my au with the bbm.I would love to see what the figures would be like with the long runners activated all the way.
_________________ 14.77 @92.71mph July 06 14.52@95.68mph July 07 14.241 96.7 MPH in a shoebox/taxi au ford wagon!!Bwahahah still cant believe it!!! |
||
| Top | |
||
| Hyena |
|
|||
|
The funny thing is with mine, peak power is the same which ever way I run it, (ie normal or all long as per the above chart) but I'm still down 20 or so kw on what it should be.
Something has happened recently that's lost power in it. It's had this flat spot for a while but some other dark forces are at work! It happened around the same time as I got new tyres, which are a higher profile than before so I thought that may have had something to do with it. I swapped my stockies back on (lower profile which have the effect of increasing the diff ratio and making it quicker) and it still doesnt feel quite as fast as before so something else is up... It also was around the same time I filled up with a tank of optimax (which I don't usually use) but obviously that couldn't have such a great effect, unless I somehow got a really bad batch ?
_________________
|
|||
| Top | |
|||
| Who is online |
|---|
Users browsing this forum: Google Adsense [Bot] and 69 guests |
