Here goes…
I have a Mk1 1.8 with some entry-level mods.
I’m keen to see how fast I can go in each gear. At present, I’m a redline virgin because I love my wee silver bucket and don’t want her to break.
Still, I can get heavy-right-foot disease and I have found that I can get 50 mph in 2nd gear and 70 mph in 3rd gear at 6,000 rpm.
My conservative estimate would therefore be 70mph in 2nd and 80 mph in 3rd at the full 7,000 rpm.
Any takers?
Le Baron 
divide by 6 to find mph per 1000rpm then multiply by 7, so at 7000 they would become 58mph in 2nd and 82mph in 3rd 
This is why she has a rev limiter. Unless you drive along permanently bouncing off the limiter, you won’t do any harm.
Try it out…when the power drops through the floor, change gear and try it out again! 
If the government has its way about 40!!!
Ah - I think I meant 60mph in 2nd; so 58 is close.
I’ll need great reserves of manfulness to go for 80+ in 3rd though; it seems so cruel…
Will try next time it’s dry. So - 2017. 
Right then - no excuses for harsh treatment. Treat 'em mean…
So, if you regularly drove the car between say, 5-7000 revs, regardless of which gear you were in and your engine was properly maintained, would it do the engine any harm or is it, as some people have suggested, healthy for an engine to do this? I grew up with long stroke engines that didn’t really rev at all and my natural inclination is to change around 4-5k. More than happy to change my driving style only if I know it won’t do any long term damage…
I believe that this is caaaaalled an “Italian Tune Up”.
I used to do this once a month in the old days of carbs.
If you constantly drive thusly, then it’s likely to reduce engine life to some extent. However, if well maintained, with lots of lovely fresh, high-pressure oil flowing, a regular bit of spirited driving is perfectly acceptable, even desirable. The healthy working range for this engine is 800 to 7,000 revs, with maximum power being delivered above 5k. It’s designed to be used…if it wasn’t, the red line would be in a different place. Mazda dealers would be full of blown-up 5’s having new engines on warranty if they got the red line in the wrong place!
In the end, where the redline is depends on how tight the tolerances in the engine are, and how big the weights that are flying around. My Honda Hornet 600 redlined at 14k and would happily spend all day long between 10k and 13k…and often did.
Agreed - from recent experience. I keep an eagle eye on the oil level, top up accordingly, allow time for the engine to reach normal working temperature, then boot it.
My mate - previous owner of my car - rated the engine so highly he was considering not selling the car to me - except he then saw a P reg M3 and bought that. He’s still jealous though as the M3 can never really be taken to the red line legally - or safely; whereas the 5 can be made to scream any time one likes.
Matron. 
Ah now legal…and safety…issues are another matter and one for your own conscience/bravery. My bike’s red line equated to 50mph in 1st gear and 70mph in 2nd. So the fun would really end there (after approx 4 secs of grinning) without ‘stretching’ the speed limits and tightening the ring somewhat. Really the bike didn’t need gears 3 to 6…ha ha.