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How competitive is a MP7.5 in 2016?

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How competitive is a MP7.5 in 2016?

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Old 04-22-2017, 05:03 PM
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The 7.5 hasn't run a single drop of fuel since I've started this thread yet I changed the setup almost monthly.

Applying things I've learnt and understood since I started this thread I can surely keep this sucker competitive, plan is to go to NEO or DNC (old plan was to go to last year's EC in Spain) and finish right behind Pros or mix with some (C main). So, compromises I've found are:
-if I want to run less caster/camber gain I have to run the old K1 steering blocks;
-rear suspension geometry could be improved a little regarding RC location, too much work to correct.
-weight bias is rear biased, too much I think.

Handling trait is the sensitivity to getting on power, where it robs the front much needed weight, already have the B blocks on the car which give less kick up so let's see if there's an improvement. Already spent most time on setting caster and bump steer (notable flaw on the car), went for a different approach on the rear geometry (return to long upper link) and will weight the car again see if a change in weight bias is in order. Found that this car isn't as good as I thought in the sense of serving as the base of my ideal buggy design, I found that my XB9 needs less new parts!
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Old 04-22-2017, 06:32 PM
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...and people complain about HB Racing taking a long time to release new parts and cars LoL! Truth be told i was planning to resurrect my TKI3 that has been sitting on a shelf for over 2 years and got part of the way, but then got put on the back burner. I can't do all r/c all the time LoL!
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Old 04-23-2017, 03:25 AM
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This is easy if you read a book like this one. Would save a few months of headaches and misunderstandings

You mentioned TKI3 and the parts I want to develop for it are now fully understood, also because you had issues with the BE assembly it all makes sense now! Sorry for not understanding you before! Oh happy day!


Interestingly enough the 7.5 as it sits has the exact concept of geometry as my street/road car! Short, angled front upper arm; almost parallel rear arms with the upper a bit shorter. As I always said, Kanai-san knew way more than others, that's why the MP platform is the most copied design.
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Old 11-08-2017, 06:35 AM
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And again with the setup changes. Found out the best geometry possible based on spearhead chassis designs,problem that geometry isn't 100% attainable on the 7.5,bummer. Now using the 777 front shock tower with upper arm high and 2.4 rear roll bar from THE Car.

That means the car will be hampered, in the 7.5 case that means the on power steering is always compromised. Other than that front upper arm slight misplacement and bump steer the car is very very competitive, lacks ground clearance because the front ride height the car was designed is 24-25mm with worn Impacts, the rear we can run 29mm or so which is too much or 24-25 which is too little. To make this car 100% competitive it would need new shock towers, A-B-C-D plates and chassis.
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Old 11-08-2017, 07:55 PM
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Originally Posted by 30Tooth View Post
And again with the setup changes. Found out the best geometry possible based on spearhead chassis designs,problem that geometry isn't 100% attainable on the 7.5,bummer. Now using the 777 front shock tower with upper arm high and 2.4 rear roll bar from THE Car.

That means the car will be hampered, in the 7.5 case that means the on power steering is always compromised. Other than that front upper arm slight misplacement and bump steer the car is very very competitive, lacks ground clearance because the front ride height the car was designed is 24-25mm with worn Impacts, the rear we can run 29mm or so which is too much or 24-25 which is too little. To make this car 100% competitive it would need new shock towers, A-B-C-D plates and chassis.
So you need an mp9?
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Old 11-09-2017, 04:28 AM
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Originally Posted by windellmc View Post
So you need an mp9?
sneaky sneaky! Not that simple as the stock MP9 can't strike that geometry, for that one needs the +2mm front end parts (I have them). The list of cars capable of that geometry and have the correct balance front and rear is actually small (no wonder you see the same brands at the top of the results sheet). Funny I was looking into the MP6 geometry because I think it can attain that geometry.

It has been fun to reverse engineer this car, shame that the "shortcomings" hamper the handling too much, other than that the car is solid or other most other cars wouldn't build on this base.
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Old 11-09-2017, 07:42 PM
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Originally Posted by 30Tooth View Post
sneaky sneaky! Not that simple as the stock MP9 can't strike that geometry, for that one needs the +2mm front end parts (I have them). The list of cars capable of that geometry and have the correct balance front and rear is actually small (no wonder you see the same brands at the top of the results sheet). Funny I was looking into the MP6 geometry because I think it can attain that geometry.

It has been fun to reverse engineer this car, shame that the "shortcomings" hamper the handling too much, other than that the car is solid or other most other cars wouldn't build on this base.
Mp6 is no match for an mp7.5.
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Old 11-10-2017, 03:27 AM
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Originally Posted by windellmc View Post
Mp6 is no match for an mp7.5.
Theoretically or do you have arguments to substantiate that claim?
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Old 11-12-2017, 11:18 AM
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Originally Posted by 30Tooth View Post
Theoretically or do you have arguments to substantiate that claim?
If you raced 1/8 in the early 2000s you would understand. Mp7.5 was practically the only car that could win races until the mbx5 came out. Even then the mbx5 was just equal, and I think that is only because kyosho refused to update their shocks until the big bores that were available for the last version of the 777. Mbx4, mp6, and Eb4 were generally no match on the track if drivers were equivalent. The Mp6 is seriously lacking steering compared to all of the cars mentioned. The diffs are also too big and heavy and this decreases the carís responsiveness.
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Old 11-12-2017, 05:49 PM
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Originally Posted by windellmc View Post
If you raced 1/8 in the early 2000s you would understand. Mp7.5 was practically the only car that could win races until the mbx5 came out. Even then the mbx5 was just equal, and I think that is only because kyosho refused to update their shocks until the big bores that were available for the last version of the 777. Mbx4, mp6, and Eb4 were generally no match on the track if drivers were equivalent. The Mp6 is seriously lacking steering compared to all of the cars mentioned. The diffs are also too big and heavy and this decreases the carís responsiveness.
I did understand but I wanted you to add further to your claim as more knowledge is better right?

Agreed, the 7.5 was a big step forward for buggies. Simple, wide, strong and low as no other before or contemporary to it. About the big bores, they were an optional on the very end of the 777 life cycle. About the mbx4, the original version (r/rr/xr excepted) the diffs were aluminium cups with attachable crowns, they weighed more than the MP6 by a mile (at least the cups were plastic and smaller than the Mugen ones), the TTR was good and all (Adam Drake was National Champ with it!) but reliability wasn't it strongest point, the diffs were like the MP7.5 which made it very light (stock this car was a match to the 7.5). Stock setup the others don't favour traction as much as the MP6 but with a little tuning the MP6 can have at least as much steering than others

Always wanted an S2 to test but parts availability and the current state of one used (don't mentioning the prices of them...) are keeping me out of one.
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Old 11-13-2017, 06:50 AM
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The only change from mbx4 to mbx5 diffs was to use machined internal gears instead of cast. Before that the Mugen guys would use ttr internal gears for reliability. The ttr and Mugen diffs are nearly identical. They hold less fluid than a kyosho diff (which is a problem in longer races) and I would bet they are lighter too. Mayfield won a national with the ttr S3 which is a small miracle and testament to his ability. Drake may have won with the Ofna but I don’t think he ever ran a ttr. Tebo ran for ttr early on.

Once kyosho went to the 3.5 mm shock shafts on the k2 their shocks were not right until the big bores.
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Old 11-13-2017, 07:50 AM
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Originally Posted by windellmc View Post
The only change from mbx4 to mbx5 diffs was to use machined internal gears instead of cast. Before that the Mugen guys would use ttr internal gears for reliability. The ttr and Mugen diffs are nearly identical. They hold less fluid than a kyosho diff (which is a problem in longer races) and I would bet they are lighter too. Mayfield won a national with the ttr S3 which is a small miracle and testament to his ability. Drake may have won with the Ofna but I donít think he ever ran a ttr. Tebo ran for ttr early on.

Once kyosho went to the 3.5 mm shock shafts on the k2 their shocks were not right until the big bores.
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Got that wrong, Richard Saxton was NC with the TTR. You are missing the early MBX4 diffs, before the R the diff cases were aluminium, only the R onwards the diffs were the ones used on the MBX5, I'm 100% sure Mugen never had machined diff internals. Yes, there were issues with the sun gears, the pins were too small and broke easily, the fix was to use TTR outdrives (which also had problems on the first batch) and internal gears, good memory windellmc. I had both, the mugen diffs aren't lighter than 7.5 diffs, especially because you can run the RRR titanium pins on the 7.5 diffs. Correct on the drivers, go all mixed up.

Almost forgot that one, the shock shafts! It's the shafts that displaced more volume so you had to run smaller bladders/diaphragms, or increase shock volume...

Thanks for the trip down memory lane!
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