fiji bob 0 Posted February 10, 2006 i know that having a dizzy`s advance curve altered isnt ideal but im pretty sure the original curve is hurting my 8v`s top end once set so that it doesnt pink on light loads. The engine has an xu10 head with xu9ja cam and 10.5:1 compression. i just wondered if anyone had a dizzy modified by them that they had used? Share this post Link to post Share on other sites
boombang 2 Posted February 10, 2006 Pete F had one done IIRC - was fine for his old setup Share this post Link to post Share on other sites
Rob_the_Sparky 9 Posted February 10, 2006 Will be interested in the results as I've had to retard mine, loosing top end power, due to mid-range pinking. I'm running an XU9 8v but with similar 10.4:1 compression. Currently got an SBC dizzy on the car that came from NickR so not sure of what they did. It has made things better but still a fair way off perfect. Rob Share this post Link to post Share on other sites
petert 587 Posted February 10, 2006 Your're on the right track. You still need 30-31 at full load, 5000 RPM. At 2500 however, you want 25 deg. at full load and just 28-30 at part throttle. Share this post Link to post Share on other sites
fiji bob 0 Posted February 14, 2006 thanks peter, do you know how much vacumn advance is added at around 2-4krpm? Share this post Link to post Share on other sites
petert 587 Posted February 15, 2006 thanks peter, do you know how much vacumn advance is added at around 2-4krpm? Just add 6-8 degrees to the full load figures, as a gradient. ie for 3000 RPM -100 kPa 36 deg. -50 kPa 36 deg. -25 kPa 32 deg 0 kPa 28 deg. Every situation is different, but that will get you started. Share this post Link to post Share on other sites
fiji bob 0 Posted February 15, 2006 just spoken to them they will try adjusting the vacumn advance on its own for a tenner if that doesnt work or it turns out the dizzy is faulty or needs to have the curve altered that will cost between £30-65. Share this post Link to post Share on other sites
Rob_the_Sparky 9 Posted February 16, 2006 Let us know how you get on, this sounds rather interesting. Share this post Link to post Share on other sites
fiji bob 0 Posted February 16, 2006 should hopefully know what difference it makes by the end of next week Share this post Link to post Share on other sites
fiji bob 0 Posted February 18, 2006 ok ive removed the vacumn advance and made sure the vacumn advance mechanism is set so that its not adding any advance problem is the engine really doesnt like it, as the vacumn advance is now loose in the dizzy is it likely to keep moving around? as the car is driveable but could get a bit interesting driving in traffic if it keeps shifting. Share this post Link to post Share on other sites
taffycrook 2 Posted February 21, 2006 I have used them for red tops and it works well as long as you know what you want, I wanted power so part throttle wasn't an issue. They are good guys and will help you if they can. Prices reasonable but in the end you want mappable ign for the best results. Share this post Link to post Share on other sites
fiji bob 0 Posted February 21, 2006 id love to but the mi will be done at some point in the future, i was interested in trying them as its fairly cheap. the guy i spoke to thought only the vacumn advance needed altering in light of the engine spec, i have got a spare dizzy lying around though.... Share this post Link to post Share on other sites
