Finally managed to get the MSD CDI to spark. Couldn’t get electronic spark advance to work correctly so I’m just going to use vacuum advance until I can work it out. Car starts instantaneously with this new engine management system and the real powerful spark makes it even better. Thanks @DaleJeffree for the ECU. running sweet now, just needs to be tuned. Just need to mount a few bits and pieces that have been left hanging, put more oil in the gearbox and I can probably take the car for a test drive.
Also looks like I scored another HD-E for my other car.
One more week until next hillclimb. Got my exhaust nearly finished just gotta weld one last hanger. Few oil leaks to solve too. Also dad adapted a 60mm magna throttle body onto the intake.
If you have some pipe laying around with a similar diameter to your throttle body I would recommend making an intake pipe, it would move the filter further away from engine heat and improve how the engine produces torque by increasing the velocity of the air entering the plenum. If you wanted to explore the idea further there are some formulas to help work out the best size and length. Its just an idea for you and it’s something you could throw together pretty quick and would likely give you a noticeable improvement.
Yes @Mick. See if you can close off the filter from all the hot air in the bay, or else move it and seal it. I guess that filter was just the right size to clamp on. From my experience a K and N that size would be fine on something with 400 plus hp.
@Mick@Mr_Gormsby
I’m not happy with it’s current position. the higher compression ratio and valve lift has increased the engine bay temperature. But because I jumped up it throttle body size I don’t think(unless I dig through dad’s intercooler piping box)there’s any laying around the correct diametre. Future plans is to build a box near the front passenger headlight and draw air from wherever is a good source. With a week to go I’m going to be pretty tight in getting this car finished as I still have to tune it and finish off a few things. If I have time I could maybe fabricate something temporary.
I’m gong to say that 60mm is way to big unless you have a 9500rpm redline. If you have time go back and forward between the two. With some really rough math a 52mm for 7000rpm or 55mm for 8000rpm (taking capacity and rpm as the only variables into account and assuming a race type set up). On the na ejde I’ve bored the throttle body out and only gone up 2mm in diameter (but am yet to fit it), but before doing that I milled the butterfly bridge/axle down and attached it with counter sunk screws. I also reduced the tapper of the angle leading from the inlet to the butterfly, which according to theory should be no more than 7deg. Remember in calculation area increases exponentially as diameter goes up.
Bugger. I’ll have to just wing it with this for the time being. That’s what I get for guestimating. Perhaps I can restrict it somehow to do the same effect or does airflow not work that way.
Sorry to have you second think the whole thing. You’ve done some much good work, I’d hate you to find only a small improvement when expecting bigger things. I hope I’m wrong. If easy to switch back and forward between the two I’d do that and see the effect. A road test would suffice but some dyno pulls would tell. I think you will loose mid range torque and the last 1/3 of your throttle travel will do nothing. Yes you could choke it to bring up air speed in the mid rev range. Be careful with the transitions in diameter. That first article I posted will give you a sense of what is happening, but it won’t tell you exactly what to do.
Thanks mate. Will do some reading tonight. To be honest Im going to be happy with the standard 77kw and better torque from the 1.6. I just got a little carried away and thought “Well if im pulling this off I may aswell go bigger X”. @JC050 This site has had some decent charade info over the years. Thanks for reminding me about this article. Ill use it as a reference for my airbox.
Am I correct in thinking you have fitted the magna throttle body as a means to have a potentiometer type TPS for your ECU? If so I would do what Mr G said and try and choke it a bit with a smaller intake pipe. General rule of thumb for pipe length is 13 inches long for an improvement at 6000rpm, add 1.7 inches for every 1000rpm you want to lower the power band or shorten by 1.7 inches for every 1000 rpm you want to raise the power band. For example if you are looking to improve torque at 4000rpm you would make the intake pipe 16.4 inches long. This is just a General rule and results may vary slightly between different engines/setups.
For the diameter you can use this formula:
square root of (cubic Inch x volumetric efficiency x maximum rpm) / (maximum air velocity x 1130) = pipe I.D
Use 180 for air velocity and 0.85 for volumetric efficiency.
Once again this is just a guide and results will vary between engines and setups. But if you youse these as a guide, then make the best you can with what you already have laying around you will be able to knock something up super quick and you will undoubtedly see some improvements.
All the guys here want to see you do well!
I wish you the best for you race
Thanks for the information fellas. I now have a more of an idea how air likes to travel through an intake. As of now I have dyno time available where I can test and try different things. It wont be before this weekend but im pretty keen to try out different intake components/etc. This week will be probably spent ECU tuning when I have free time in the afternoons. Hopefully I can get at close enough where I can do final touchups at the race. I have a wideband AFR gauge mounted to make this possible.
Gave it a test drive and it feels great. Quite a lot of torque down low. Afr didn’t go above 14 and didn’t go below 10. No point saying more until I have actual Dyno figures.
little tidier now.
