Well slap me stupid! That is the first TRULY INNOVATIVE thing I have seen in a while. [img]graemlins/thumbs_up.gif[/img]
<font size="2" face="Verdana, Helvetica, sans-serif">Ab-so-lute-ly brilliant! I love it. [img]graemlins/heart.gif[/img]Originally posted by rmcdaniels:
It's done, and it works well, even better than I thought it would.
I do hope you're going to upgrade to the Whipple unit you showed us earlier!
Mark.
<font size="2" face="Verdana, Helvetica, sans-serif">Ab-so-lute-ly brilliant! I love it. [img]graemlins/heart.gif[/img]Originally posted by mgro:
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by rmcdaniels:
It's done, and it works well, even better than I thought it would.
I do hope you're going to upgrade to the Whipple unit you showed us earlier!
Mark.</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks, I'll get the Whipple running at some point, but the next thing I'm building is a N/A setup using a Dart tall-deck block and a 95mm crank. It'll have ITB's, Hall effect cam gear timing setup, COP, big cams, the works. All the parts are in for it, it just needs to be assembled and put in the car.
I hope you're still following this thread...
I followed your thread on HT, and I've been pondering the dyno charts you posted. As an HT member pointed out, the difference between the "turbo only" and "dual charger" curves is not earthshattering. I realize that the charts only confer information about the static case: the throttle response is probably much, much better. But I cannot help thinking that more static advantage should be achievable. Is it possible that when the turbo hasn't spooled yet, the blower has trouble drawing air through the turbo? A restriction at the supercharger's inlet would effectively kill the performance! It may be interesting to measure the vacuum between the turbo and the blower at WOT before the turbo has spooled. If you find significant vacuum it may be beneficial to incorporate another bypass valve, only this time around the turbo!
Mark.
<font size="2" face="Verdana, Helvetica, sans-serif">Thanks Mark, that's a really good idea, and easy to implement as my boost gauge measures vacuum and I have a couple of air nipples pre-SC. I'll just shuffle a couple of vacuum lines around and see. I hadn't thought too much about the intake restriction, but it could explain why the SC is making less initial boost than it should. I've been tweaking the bypass assembly to make sure it is tight and operating correctly so I don't get any bypass before I want it, but that's pretty well done now. I could use a simple flap valve between the charge pipe and the CAI pipe, and that would have the additional benefit of filling up the last little bit of clear space under my hood. Arguably pulling airflow through the impeller could help spool the turbo faster, but the benefit may be outweighed by the restriction in the intake path.Originally posted by mgro:
I hope you're still following this thread...
I followed your thread on HT, and I've been pondering the dyno charts you posted. As an HT member pointed out, the difference between the "turbo only" and "dual charger" curves is not earthshattering. I realize that the charts only confer information about the static case: the throttle response is probably much, much better. But I cannot help thinking that more static advantage should be achievable. Is it possible that when the turbo hasn't spooled yet, the blower has trouble drawing air through the turbo? A restriction at the supercharger's inlet would effectively kill the performance! It may be interesting to measure the vacuum between the turbo and the blower at WOT before the turbo has spooled. If you find significant vacuum it may be beneficial to incorporate another bypass valve, only this time around the turbo!
Mark.
And the dyno chart does only tell part of the story. I took the car to an autocross this weekend, probably the worst type of racing for a high-HP turbo Honda. I've done it in the past and had fun, but it was wheel spinning, tire smoking, gravel spitting fun. This time power delivery was smooth and I had no traction issues. The other thing with autocross is that I was in an out of the throttle very frequently, which would usually mean spooling up the turbo each time, but with this setup it's not an issue, I just had smooth controllable power whenever I needed it.
<font size="2" face="Verdana, Helvetica, sans-serif">I'd love to hear the results of that experiment!Originally posted by rmcdaniels:
Thanks Mark, that's a really good idea, and easy to implement as my boost gauge measures vacuum and I have a couple of air nipples pre-SC. I'll just shuffle a couple of vacuum lines around and see. I hadn't thought too much about the intake restriction, but it could explain why the SC is making less initial boost than it should.
<font size="2" face="Verdana, Helvetica, sans-serif">Would you say the throttle response is the same as it was with just the blower?
This time power delivery was smooth and I had no traction issues. The other thing with autocross is that I was in an out of the throttle very frequently, which would usually mean spooling up the turbo each time, but with this setup it's not an issue, I just had smooth controllable power whenever I needed it.
One more Q... the blower will spit out very hot air at high boost levels, whereas the turbo with intercooler generates nice&cool air. The stock IAT sensor is quite slow, it has a time constant of several seconds at least. So when the butterly starts to open the IAT will quite suddenly start to drop. How did you compensate for this effect?
Mark
<font size="2" face="Verdana, Helvetica, sans-serif">I'd love to hear the results of that experiment!Originally posted by mgro:
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by rmcdaniels:
Thanks Mark, that's a really good idea, and easy to implement as my boost gauge measures vacuum and I have a couple of air nipples pre-SC. I'll just shuffle a couple of vacuum lines around and see. I hadn't thought too much about the intake restriction, but it could explain why the SC is making less initial boost than it should.
<font size="2" face="Verdana, Helvetica, sans-serif">Would you say the throttle response is the same as it was with just the blower?
This time power delivery was smooth and I had no traction issues. The other thing with autocross is that I was in an out of the throttle very frequently, which would usually mean spooling up the turbo each time, but with this setup it's not an issue, I just had smooth controllable power whenever I needed it.
One more Q... the blower will spit out very hot air at high boost levels, whereas the turbo with intercooler generates nice&cool air. The stock IAT sensor is quite slow, it has a time constant of several seconds at least. So when the butterly starts to open the IAT will quite suddenly start to drop. How did you compensate for this effect?
Mark</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">There's no vacuum between the SC and the turbo when I open the throttle, but I found another problem. Here's what I wrote on H-T about it:
"It was still building boost inconsistently, sometimes really fast, sometimes dog slow, so I set up a test bench with some air and a few valves and regulators to simulate operation under load. I figured out the problem, my analog feedback loop was a total POS and it was causing the diverter assembly to only partially open, and at the wrong time. I put together a digital feedback loop to control the diverter tonight and it works much better now. It builds boost much faster and every pull is exactly the same. The car feels much faster. The transition is not as smooth, although I still can't feel it on the butt-dyno, but if I watch the boost gauge then I can see the switchover. I'll try to get it on the dyno in the next day or two and see what kind of difference it made."
As far as the IAT goes, it's mostly for informational purposes. The AFR is tuned using a wideband O2 sensor. Also because I bypass the blower before it gets up to high RPM's, the temperature delta is nowhere near as bad as it would be for a straight JRSC setup.
Throttle response is still pretty good, about like any JRSC car, far better than a turbo. I was concerned because I was moving the throttle body farther away from the intake, but it doesn't seem to have adversely affected it.
<font size="2" face="Verdana, Helvetica, sans-serif">Thanks for taking the time to answer my questions, I appreciate that! I'll subscribe to the H-T thread to keep up to date with your projects results.Originally posted by rmcdaniels:
There's no vacuum between the SC and the turbo when I open the throttle, but I found another problem. Here's what I wrote on H-T about it:
Throttle response is still pretty good, about like any JRSC car, far better than a turbo. I was concerned because I was moving the throttle body farther away from the intake, but it doesn't seem to have adversely affected it.[/QB]
Keep up the good work,
Mark.
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