SimonB Posted August 11, 2004 Share Posted August 11, 2004 RPM is a pulsed signal anyway, not like the MAP sensor which is a linear voltage thingy that can be clamped at a particular voltage. You would have to build a device similar to a speed convertor. You could then put that between something like an Emanage and the ECU so the Emanage saw the true RPM signal and based its maps on that, then the ECU would see a clamped signal and therefore not have a rev limit. I'm sure someone like Pete could build something, but I doubt if there is anything off the shelf that would do it. Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 11, 2004 Share Posted August 11, 2004 Originally posted by TLicense However, my point is still valid. The difference in duty cycle from 7500 RPM's to 8000 RPM's will be a lot more than you'd want it to be. Can't remember exactly but I think the last 500 RPM on my fuel map sees the duty increase from 95 to over 100% (Not to worry as my rev limiter is set way lower than that anyway!) What I'm saying, is you'd run 'orribly lean, at a point where you're at high boost AND high revs. I know my puny 440's will porbably be running a lot leaner than whatever gargantuam injectors john will be running, but he's going to be needing that fuel a lot more than I would. I suppose if money was no object, then that would indeed be the way to go, letting the engie let go as you charge over the line. but is your map correct. Mine was exactly the same between 7500 & 8000 rpm. we would obviously check it and it was purely a thought. Simon seems very on the ball. BTW what happens when we run more boost that the stock MAP range? Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted August 11, 2004 Share Posted August 11, 2004 Bearing in mind that the fuel computer, (in Dudes case, the SAFC), is only mapped up to 7000 rpm, and at this point, it's backed off by quite a large percentage, as it got to 8000rpm, the AFC would be well out of it's range so the fuelling would be richened up quite a lot. It certainly wouldn't be dangerous in that respect. Too rich if anything. I still say get a manual diff. Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 11, 2004 Share Posted August 11, 2004 You need all the gearing you can get to keep up with me ;-) Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted August 11, 2004 Share Posted August 11, 2004 Originally posted by Terry S You need all the gearing you can get to keep up with me ;-) Yeah yeah..... Nutter! You must have a T88 on that deisel engine! Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 11, 2004 Share Posted August 11, 2004 Feel the power of a Navara......... Ray Hall does an upgrade LOL Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted August 11, 2004 Share Posted August 11, 2004 Originally posted by Terry S Feel the power of a Navara......... Well I would have, but you disapeared into the distance and not amount of 'stupid' driving over a 100 mile stretch could catch you... I think you pulled into a service layby and hid from us! As for the upgrade, I'm half way there, my car sound like a diesel at idle! Next time mate... Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 11, 2004 Share Posted August 11, 2004 I am gonna trackday it LOL Quote Link to comment Share on other sites More sharing options...
TLicense Posted August 11, 2004 Share Posted August 11, 2004 Originally posted by SimonB RPM is a pulsed signal anyway, not like the MAP sensor which is a linear voltage thingy that can be clamped at a particular voltage. You would have to build a device similar to a speed convertor. You could then put that between something like an Emanage and the ECU so the Emanage saw the true RPM signal and based its maps on that, then the ECU would see a clamped signal and therefore not have a rev limit. I'm sure someone like Pete could build something, but I doubt if there is anything off the shelf that would do it. Ahh yes, pulsed. Forgot about that. Theories the same though. I don't know how the e-manage works. Does it have it's own complete maps or does it fudge the output of the ecu (which, like I said is what most "piggy back" computers do) I'm a bit confussed by what Matt said, why would the SAFC be backed off at 7000 rpm? If he's running at all rich at this point then he's losing power. I did think that maybe one way of getting around it would be to do this, but then you'd be losing the competetive edge at 7000 rpm, in which case he might as well just leave it as it is and change gear. To be honest it's a moot point anyway. At the level of competition that John's at, he really shouldn't be "bodging" something together. The way I see it it comes down to the three tests I mentioned earlier. Regards Tony Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 11, 2004 Share Posted August 11, 2004 Originally posted by TLicense To be honest it's a moot point anyway. At the level of competition that John's at, he really shouldn't be "bodging" something together. The way I see it it comes down to the three tests I mentioned earlier. Take exception at that mate, we did it to prove a point to other "tuners" and I think we have in a pretty spectacular way don't you. We never said rich made more power, just "safe". You want's more revs first. Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 11, 2004 Share Posted August 11, 2004 Originally posted by Terry S but is your map correct. Mine was exactly the same between 7500 & 8000 rpm. we would obviously check it and it was purely a thought. Simon seems very on the ball. BTW what happens when we run more boost that the stock MAP range? Don't start me on that again Theoretically, you could clamp the rpm signal to the ECU given the correct electronics. You could control extra fuelling using the E-manage by feeding it the actual rpm and mapping additional injector duty or even adjusting the airflow signal. However. The stock ECU fires each injector and each igniter itself. It in fact *outputs* the tachometer signal. It works out the TACH signal by it's crank position sensor. Which means clamping the TACH signal would only affect the rev counter... You'd have to clamp the CPS signal and that will mean the injectors and sparks will fire at that clamped value's timings no matter how much faster the engine spins. That'd make my misfire look like a McLaren tuned engine.... I don't know all this for sure but I think this is a rather important consideration. -Ian Quote Link to comment Share on other sites More sharing options...
SimonB Posted August 11, 2004 Share Posted August 11, 2004 Ah yes, good point there Ian! Quote Link to comment Share on other sites More sharing options...
TLicense Posted August 12, 2004 Share Posted August 12, 2004 Originally posted by Terry S Take exception at that mate, we did it to prove a point to other "tuners" and I think we have in a pretty spectacular way don't you. We never said rich made more power, just "safe". You want's more revs first. I think you've misinterpreted my post, or maybe I didn't phrase it particularly well. What I meant is Dude's car is an excellent piece of engineering. If I was at the stage of modification that he is, I just wouldn't like to see something cobbled together to get around the fact that I couldn't correctly raise the rev limit within the ecu, or have the the correct gearing. I certainly wasn't questioning the workmanship to date. Either way, Ian's point has fried that idea anyway. Quote Link to comment Share on other sites More sharing options...
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