wld 3 Posted September 2, 2019 I'm rebuilding a Bx 16V (d6c engine with PeterT inlet camshaft) which will be used mainly as a classic car, but I wouldn't mind some spirited driving when possible. I'd like to drive it during some holidays, and to some remote car shows, so highway driving may be a big part of the trips. As I recall from almost 10 years ago when it was still usable, that was not a very pleasant experience (over 4000rpm at 135km/h or around 85mph) I have 2 mi16 gearboxes and one from a 1.6gti, and I can get a 5th from a TD box (0.66 I think) I have two options, and was seeking info for which may be best option 1: 1.6 gti gearbox, 4.03 final drive, with 0.76 5th from the mi option 2: mi gearbox, 4.44 final drive, with 0.66 5th from the TD box I fear option 2 may result in a too long 5th, and option1 may compromise diveability in intermediate gears as the car weighs around 1050kg, maybe more, considering it has original sunroof and A/C Any thoughts? Share this post Link to post Share on other sites
Tom Fenton 1,518 Posted September 2, 2019 Almost this exact question was asked very recently. Have a search of the topic, I will see if I can find it. Share this post Link to post Share on other sites
Tom Fenton 1,518 Posted September 2, 2019 https://www.205gtidrivers.com/forums/topic/173626-what-ratios-to-choose-standard-mi16-engine/ Share this post Link to post Share on other sites
jackherer 543 Posted September 2, 2019 I used to daily drive BX 16vs for years and I never had a problem with the RPM in fifth, if you change it you'll compromise performance which seems to defeat the object of having a 16v to me. I think part of the problem might be that a lot of people are only familiar with low revving diesel engines (or to a lesser degree turbo petrol engines) now so an older NA petrol car that revs over 7k seems too high. Share this post Link to post Share on other sites
wld 3 Posted September 2, 2019 I used to daily drive the car in question for about 7 years, but last time I drove it was in 2010. It seems I'm older and softer It seems I'd better use some dynamat or similar soundproofing and leave the gearbox alone. 1 Share this post Link to post Share on other sites
wld 3 Posted September 2, 2019 2 hours ago, Tom Fenton said: https://www.205gtidrivers.com/forums/topic/173626-what-ratios-to-choose-standard-mi16-engine/ Thanks! It was just under my nose Share this post Link to post Share on other sites
petert 549 Posted September 3, 2019 Mi16x4 is shorter and it's a better touring car. That's all I'd swap to. Share this post Link to post Share on other sites
wld 3 Posted September 4, 2019 0.81 instead of 0.76? I saw your post about the best combo on the other topic and I was just about to ask if the shorter 3rd and 4th (1.36 and 1.069) make a noticeable difference? Does the car feel much more lively on A/B roads? If so, I can pair the 1.6gti gearbox with the 4.43 cwp but I'll have to source a hard to find 0.81 fifth or live with the gap... 0.81 with 4.43 final drive It's probably better for 110-120km/h but on european highways we drive like lunatics and 135-140km/h is considered a moderate speed in some countries. For example, in Bulgaria, they upped the limit to 140km/h and +9km/h is still acceptable by the police, so driving almost 150 (90mph) is perfectly legal. Of course, I don't have to drive that fast, especially with a 30 yo car... Share this post Link to post Share on other sites
petert 549 Posted September 4, 2019 Yes, 0.81. I see your point, but the gap is huge from 1.069 to 0.76. The shorter gears are much better, even with a 2L engine. Share this post Link to post Share on other sites