Papercup's V8 RX7
Discussion
4packet said:
Thanks for your detailed response! Would be great to see some pics of it completed. The steering rack position vs bonnet modification is also something I'm weighing up. While it is possible to lower the engine sufficiently to clear stock bonnet it does involve bump steer corection on the steering arms which I don't like the idea of. I'm also struggling to find any mention online of the sump to road clearance. Are you happy with your ground clearance?
Martin
Not sure about any of that; I didn't do that work. I know Craig is working on new steering thingies to stop the bump steer. I was going to get a set when I am next up there.Martin
I assume he got the engine pretty low as the strut brace is still there (but had to be spaced up about a centimetre).
I am happy with ground clearance; my lowest point is the back of the exhaust mid-box, and I am running sensible heights these days as I want to drive the car and be able to drive over speed bumps without issues. Its fine.
Rex is home 
Rex is also wearing his BBS LMs as the Volks are just too minty-mint to be fitted when the car is anywhere near a bodyshop
They are a different look for Rex. So different do they look, that I honestly love the look of either, and couldn't say I preferred one over the other. See the first thread here (when Rex was a rotary) for a selection of pics of both if you want to make your mind up Generally he wears the Volks recently as they have the road tyres on, and the LMs have the 888s for sprinting/track/etc.
Not only is it all shiny and happy, with the new paint over the entire front end and one door, but the mop has been out and all the work mentioned in the previous page has been done. My R-Magic bonnet has returned!
Oh, and last week I found a pair of the best-looking headlamps you can get for a Rex. Craig had sweated blood and uttered almost continuous swear-words at my insistence on keeping those pop-ups, but they can be improved on. I give you......the Knightsports twin pop-ups:
I'd missed a few sets of these before on the forum over the last few years, they go for £500-odd second-hand which gives you some idea of what they cost new from Japan, but the chance of finding a set when the car is in a bodyshop and simply begging for them to be fitted was one not to be missed. One late-night dash to Watford and back and they were delivered to the bodyshop by me the next day. They are a quality piece of kit. As they 'pop-up' less than the standard ones, they aren't just new lights, but instead the complete rotating metal assembly that bolts to the slam panel, and uses the same motors. An electrical kit that plugs into the existing bulb-plug and controls them using relays finishes them off. They were still a bit of a sod to fit, and require a bit of butchering of the standard light covers (they use the same ones, but need modding slightly) but as we had new ones it allowed the bodyshop to practice with the old ones first, and get them perfect. I also had the bezels painted the same gloss black as the rest of the car, so they look fantastic, and match the car perfectly, much better than the standard ones that look a bit naff, and have dull grey plastic surrounds.
While we are here, why not a few with the bonnet up, to remind you how well this tiny new motor fits
Last but not least, the latest shot of the radiator. Contrast this to the stuff on page 5 of this thread, you can see how the radiator has been dropped that vital 3 inches to make it flush with the undertray to stop any air getting under it. Also, how the fan has changed from the front (bad!) to the back (good!) and got bigger and with a chunkier motor on it. We'll see how the temperatures do as we roll slowly into spring and summer.
BEFORE
AFTER
Rex is also wearing his BBS LMs as the Volks are just too minty-mint to be fitted when the car is anywhere near a bodyshop
They are a different look for Rex. So different do they look, that I honestly love the look of either, and couldn't say I preferred one over the other. See the first thread here (when Rex was a rotary) for a selection of pics of both if you want to make your mind up Generally he wears the Volks recently as they have the road tyres on, and the LMs have the 888s for sprinting/track/etc.Not only is it all shiny and happy, with the new paint over the entire front end and one door, but the mop has been out and all the work mentioned in the previous page has been done. My R-Magic bonnet has returned!
Oh, and last week I found a pair of the best-looking headlamps you can get for a Rex. Craig had sweated blood and uttered almost continuous swear-words at my insistence on keeping those pop-ups, but they can be improved on. I give you......the Knightsports twin pop-ups:
I'd missed a few sets of these before on the forum over the last few years, they go for £500-odd second-hand which gives you some idea of what they cost new from Japan, but the chance of finding a set when the car is in a bodyshop and simply begging for them to be fitted was one not to be missed. One late-night dash to Watford and back and they were delivered to the bodyshop by me the next day. They are a quality piece of kit. As they 'pop-up' less than the standard ones, they aren't just new lights, but instead the complete rotating metal assembly that bolts to the slam panel, and uses the same motors. An electrical kit that plugs into the existing bulb-plug and controls them using relays finishes them off. They were still a bit of a sod to fit, and require a bit of butchering of the standard light covers (they use the same ones, but need modding slightly) but as we had new ones it allowed the bodyshop to practice with the old ones first, and get them perfect. I also had the bezels painted the same gloss black as the rest of the car, so they look fantastic, and match the car perfectly, much better than the standard ones that look a bit naff, and have dull grey plastic surrounds.
While we are here, why not a few with the bonnet up, to remind you how well this tiny new motor fits
Last but not least, the latest shot of the radiator. Contrast this to the stuff on page 5 of this thread, you can see how the radiator has been dropped that vital 3 inches to make it flush with the undertray to stop any air getting under it. Also, how the fan has changed from the front (bad!) to the back (good!) and got bigger and with a chunkier motor on it. We'll see how the temperatures do as we roll slowly into spring and summer.
BEFORE
AFTER
Neil needs to read the whole thread Goodwood, last Saturday
First trackday since the 'ring last October, and all the recent temperature-related mods (vented bonnet, larger fan, relocation of fan from front to back, moving radiator down to remove gap beneath it) and I think its safe to say we've fixed the temperature problems.
Bear in mind I was lapping the 'ring at 110 degrees water and oil. Thanks to my wonderful new gauges (which I really must do a post about on their own, as I haven't even pictured them here, and they are properly nice bits of kit that truly impress) I can reset the output and they will then hold the maximum they have reached and a quick button press shows you what that is.
So.....weather was nice. Overcast but sunny, and the sun would break through the clouds every now and then. The sort of day when if the sun is out its nice, but in the shade you needed a jacket.
Hottest temps I saw all day were:
89 water
99 oil
...and thats under continued fast lapping (1:30 -ish laps)
Anyone got any idea of those temperatures are good or not? I would say that once the oil got over 90 the car was hot inside; the shell heats up and you can feel the roll cage heating your leg (where it rests against the vertical pipe that comes down by the dashboard), and heat would pour out of the trim either side of the centre console. Also, I could feel that my shins and feet were warm. Must get that air-con working!
Car was impressive though; I know Goodwood well and I was belting round, wasting most things. I am going to sprint there next month and those times will tell me if the car is the same; it certainly feels it. I've done a 90 second standing-start lap there before.
Rex was VERY popular. Steady stream of people all day wanting to see what was in it, and just why it sounded so funny.....several people came up and said 'thats not a rotary is it?'. I spent as much time talking about it as I did driving it. It helped that I'd washed it the day before; she was very clean and looked fantastic in the sun.
Its much easier now to play with oversteer at the chicane Just prod the throttle a little too much and..... 
All in all it was a really good day out.
Problems? Well, the back-box has been dying for a while. It was noticeable recently on the road at high revs; a sound like someone tearing sheets of thin metal that would drown out the engine. Not nice. I've blown the guts out of it, and whats left has sheared off and is vibrating. As you can imagine caning the pants off it at Goodwood lap after lap did this no favours; by mid-afternoon you could only hear that nasty sound trackside, and I decided to stop as I was starting to get filthy looks from the noise people.
Speaking of noise, I only just got through the noise test at the start of the day, probably to do with this damage; initially tested at 108db, we raised the revs really slowly and got through at 102db. For a laugh the noise guy held it over the bonnet and got 109! But no problems on track with the driveby meters, which are usually the issue. I spent the morning being careful past them but was flat-out in the afternoon with not one peep. Great news about the drivebys, but the static stuff may be a problem at certain tracks.
I also, in that last session, managed to blow the exhaust apart behind the mid-box; the ring clamp must not have been up to the job. We put it back in but I want that join changing to the same method as the others; a proper flange with nuts and bolts; then it can't happen again.
cheers
Andy
First trackday since the 'ring last October, and all the recent temperature-related mods (vented bonnet, larger fan, relocation of fan from front to back, moving radiator down to remove gap beneath it) and I think its safe to say we've fixed the temperature problems.
Bear in mind I was lapping the 'ring at 110 degrees water and oil. Thanks to my wonderful new gauges (which I really must do a post about on their own, as I haven't even pictured them here, and they are properly nice bits of kit that truly impress) I can reset the output and they will then hold the maximum they have reached and a quick button press shows you what that is.
So.....weather was nice. Overcast but sunny, and the sun would break through the clouds every now and then. The sort of day when if the sun is out its nice, but in the shade you needed a jacket.
Hottest temps I saw all day were:
89 water
99 oil
...and thats under continued fast lapping (1:30 -ish laps)
Anyone got any idea of those temperatures are good or not? I would say that once the oil got over 90 the car was hot inside; the shell heats up and you can feel the roll cage heating your leg (where it rests against the vertical pipe that comes down by the dashboard), and heat would pour out of the trim either side of the centre console. Also, I could feel that my shins and feet were warm. Must get that air-con working!
Car was impressive though; I know Goodwood well and I was belting round, wasting most things. I am going to sprint there next month and those times will tell me if the car is the same; it certainly feels it. I've done a 90 second standing-start lap there before.
Rex was VERY popular. Steady stream of people all day wanting to see what was in it, and just why it sounded so funny.....several people came up and said 'thats not a rotary is it?'. I spent as much time talking about it as I did driving it. It helped that I'd washed it the day before; she was very clean and looked fantastic in the sun.
Its much easier now to play with oversteer at the chicane
Just prod the throttle a little too much and..... All in all it was a really good day out.
Problems? Well, the back-box has been dying for a while. It was noticeable recently on the road at high revs; a sound like someone tearing sheets of thin metal that would drown out the engine. Not nice. I've blown the guts out of it, and whats left has sheared off and is vibrating. As you can imagine caning the pants off it at Goodwood lap after lap did this no favours; by mid-afternoon you could only hear that nasty sound trackside, and I decided to stop as I was starting to get filthy looks from the noise people.
Speaking of noise, I only just got through the noise test at the start of the day, probably to do with this damage; initially tested at 108db, we raised the revs really slowly and got through at 102db. For a laugh the noise guy held it over the bonnet and got 109! But no problems on track with the driveby meters, which are usually the issue. I spent the morning being careful past them but was flat-out in the afternoon with not one peep. Great news about the drivebys, but the static stuff may be a problem at certain tracks.
I also, in that last session, managed to blow the exhaust apart behind the mid-box; the ring clamp must not have been up to the job. We put it back in but I want that join changing to the same method as the others; a proper flange with nuts and bolts; then it can't happen again.
cheers
Andy
Edited by papercup on Tuesday 29th March 16:34
papercup said:
...and thats under continued fast lapping (1:30 -ish laps)
Anyone got any idea of thats good or not?
Andy, in my Austin A35 I have just scraped a high 1:38 on a flying lap, so yes very quick!! Although I was on crossply rubber and pushing around 120mph down the straight! Your RX7 is an awesome car, and the degree of work that has gone into it is fabulous. Must say it looks gorgeous on those BBSs too... Anyone got any idea of thats good or not?
Chunkychucky said:
papercup said:
...and thats under continued fast lapping (1:30 -ish laps)
Anyone got any idea of thats good or not?
Andy, in my Austin A35 I have just scraped a high 1:38 on a flying lap, so yes very quick!! Although I was on crossply rubber and pushing around 120mph down the straight! Your RX7 is an awesome car, and the degree of work that has gone into it is fabulous. Must say it looks gorgeous on those BBSs too... Anyone got any idea of thats good or not?
I've done a 1:30 from a standing start on the grid, so I wasn't particularly impressed by the 1:30 flying lap.
I hate my T56.
If there's one thing that makes me sell this whole thing, it'll be the s
tty box.
High speed/revs is fine, but changing into 2nd, 3rd, 5th.. (well pretty much any gear. 4th is often best of the lot) at low revs is horrible.
This weekend I will be de-shimming the detent spring on the side of the box. This is the ball/spring that causes the shifter to slam into centre before moving up/down into the next gear - it creates the "notch wall" that you feel in between shifts. I shimmed it out totally when I refitted the box after replacing all the synchro blockers. Maybe this is messing with the shift action. I'm also not totally convinced how much fluid is in the box. I overfilled it on purpose, and the next day I checked it and I couldn't feel any fluid through the reverse-switch hole, which is where you're supposed to feel the level up to. I could be leaking out of my detent spring shim.. I dunno.
Papercup: You never said which diff you have on your car. As Efiniste mentioned, there's a lower ratio RX7 LSD available - the one from the automatic cars. It's 3.91:1 instead of 4.09:1. That improves things a bit, although first is still less than ideal.
I just bought another one (3.91 LSD), from a 1999 car, because I thought mine had slop in it that might have been contributing to the stty gear shifts. Turns out my old diff is utterly perfect, and a day was wasted! At least I didn't lose a thumbnail this time fitting the diff - the transmission jack has definitely served me well to date, and made the diff swap an almost breeze.
With the 3.91 rear end, your in-gear speeds, with a GTO T56 like you and I both have, are as follows:
If there's one thing that makes me sell this whole thing, it'll be the s
tty box.High speed/revs is fine, but changing into 2nd, 3rd, 5th.. (well pretty much any gear. 4th is often best of the lot) at low revs is horrible.
This weekend I will be de-shimming the detent spring on the side of the box. This is the ball/spring that causes the shifter to slam into centre before moving up/down into the next gear - it creates the "notch wall" that you feel in between shifts. I shimmed it out totally when I refitted the box after replacing all the synchro blockers. Maybe this is messing with the shift action. I'm also not totally convinced how much fluid is in the box. I overfilled it on purpose, and the next day I checked it and I couldn't feel any fluid through the reverse-switch hole, which is where you're supposed to feel the level up to. I could be leaking out of my detent spring shim.. I dunno.
Papercup: You never said which diff you have on your car. As Efiniste mentioned, there's a lower ratio RX7 LSD available - the one from the automatic cars. It's 3.91:1 instead of 4.09:1. That improves things a bit, although first is still less than ideal.
I just bought another one (3.91 LSD), from a 1999 car, because I thought mine had slop in it that might have been contributing to the s
tty gear shifts. Turns out my old diff is utterly perfect, and a day was wasted! At least I didn't lose a thumbnail this time fitting the diff - the transmission jack has definitely served me well to date, and made the diff swap an almost breeze.With the 3.91 rear end, your in-gear speeds, with a GTO T56 like you and I both have, are as follows:
I should be back at Craig's in a few weeks to finish off some stuff and fix the exhaust up. Hoepfully I'll get to drive the Rex he finished recently with the TR6060 box. Craig says its loads better.
Oh, I do have the auto diff. Your calculations seem spot on with the in-gear speeds; I was a whisker off the redline in 5th down the back straight at Goodwood, and the satnav claimed 140.
Still not sure where to go next; I could get a TR6060 or Magnum but the gear ratios are still screwed. This car wants a 3.3/3.4 diff really, then the gears would make more sense and 6th would be a true overdrive. I was looking at the gear ratios for the Corvette ZR-1 the other day; its geared for 205 in 5th, and 6th is just for MPG. With the power-to-weight of the Rex that makes more sense than what I have now (which is a gearbox I don't EVER even use 1st gear in, and I run out of puff at 140 as i hit the top of 5th and then 6th is a lifetime away.
Corvette ZR-1:
Gear Type Close Ratio 6-Speed Manual
Final Drive 3.42:1
1st Gear Ratio 2.29:1
2nd Gear Ratio 1.61:1
3rd Gear Ratio 1.21:1
4th Gear Ratio 1:1
5th Gear Ratio 0.81:1
6th Gear Ratio 0.67:1
Compared to what I have:
Final Drive 3.91:1
1st Gear Ratio 2.97:1
2nd Gear Ratio 2.07:1
3rd Gear Ratio 1.43:1
4th Gear Ratio 1:1
5th Gear Ratio 0.84:1
6th Gear Ratio 0.57:1
I can get a Magnum with those same ratios as the Corvette, the close ratio box.
Craig is working towards making a fitting kit for a Cobra diff, and you can have that in any ratio you want. Needs new half-shafts though (which Craig alwready has in his, and a Viper diff). Cobra diff looks a lot bigger than the Rex one buts its ally so actually weighs less.
One of those and a nice TR6060 or Magnum (whichever is smoother). Nice. The way forward?
Andy
Oh, I do have the auto diff. Your calculations seem spot on with the in-gear speeds; I was a whisker off the redline in 5th down the back straight at Goodwood, and the satnav claimed 140.
Still not sure where to go next; I could get a TR6060 or Magnum but the gear ratios are still screwed. This car wants a 3.3/3.4 diff really, then the gears would make more sense and 6th would be a true overdrive. I was looking at the gear ratios for the Corvette ZR-1 the other day; its geared for 205 in 5th, and 6th is just for MPG. With the power-to-weight of the Rex that makes more sense than what I have now (which is a gearbox I don't EVER even use 1st gear in, and I run out of puff at 140 as i hit the top of 5th and then 6th is a lifetime away.
Corvette ZR-1:
Gear Type Close Ratio 6-Speed Manual
Final Drive 3.42:1
1st Gear Ratio 2.29:1
2nd Gear Ratio 1.61:1
3rd Gear Ratio 1.21:1
4th Gear Ratio 1:1
5th Gear Ratio 0.81:1
6th Gear Ratio 0.67:1
Compared to what I have:
Final Drive 3.91:1
1st Gear Ratio 2.97:1
2nd Gear Ratio 2.07:1
3rd Gear Ratio 1.43:1
4th Gear Ratio 1:1
5th Gear Ratio 0.84:1
6th Gear Ratio 0.57:1
I can get a Magnum with those same ratios as the Corvette, the close ratio box.
Craig is working towards making a fitting kit for a Cobra diff, and you can have that in any ratio you want. Needs new half-shafts though (which Craig alwready has in his, and a Viper diff). Cobra diff looks a lot bigger than the Rex one buts its ally so actually weighs less.
One of those and a nice TR6060 or Magnum (whichever is smoother). Nice. The way forward?
Andy
Going further:
Check out Rockland Standard Gear and click on 'Tremec T56 Magnums Built to Son Of Tranzilla Specs...'
This is the people recommended to me by Craig; they built his T56 (back before the TR6060 and Magnum (which is TR-6060-based)) into something stronger after he killed it drag racing.
You can see they offer three choices. Check out the close ratio one (No.3). See how the ratios are almost exactly the same as the ZR-1 I put in the post above.
Combine with a Cobra diff at 3.42 (same as ZR-1 again) and my tyre profile at the back being 40, not the 35 you put, and that gives me:
Now THAT is food for thought.....
Check out Rockland Standard Gear and click on 'Tremec T56 Magnums Built to Son Of Tranzilla Specs...'
This is the people recommended to me by Craig; they built his T56 (back before the TR6060 and Magnum (which is TR-6060-based)) into something stronger after he killed it drag racing.
You can see they offer three choices. Check out the close ratio one (No.3). See how the ratios are almost exactly the same as the ZR-1 I put in the post above.
Combine with a Cobra diff at 3.42 (same as ZR-1 again) and my tyre profile at the back being 40, not the 35 you put, and that gives me:
Now THAT is food for thought.....
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