Jump to content
SAU Community

Os Giken 5 Speed Vs Ppg Straight Cut/helical Cut Dog Gears Vs Sequentials


Piggaz

Recommended Posts

Let us know your thoughts on the dog box after you have a drive with one Piggaz. I'm going to be in the same boat as you and am not sure about driving with one on the street.

CHeers

Will do. Either way, decision is made so ill just have to learn.

What's your setup?

Link to comment
Share on other sites

They are easy on the street. To be honest, they do take a week or two to adjust to the new style of changing gear and the change in speeds you get in each gear. If i push mine to 8000rpm my speedo just nudges 100kph in first gear! Power levels, final drives and tyre size do affect this. .

Once you get the hang of no clutch, you will never want to go back a synchro box. You realise they are purely for comfort and that is it!

Link to comment
Share on other sites

They are easy on the street. To be honest, they do take a week or two to adjust to the new style of changing gear and the change in speeds you get in each gear. If i push mine to 8000rpm my speedo just nudges 100kph in first gear! Power levels, final drives and tyre size do affect this. .

Once you get the hang of no clutch, you will never want to go back a synchro box. You realise they are purely for comfort and that is it!

Can you downshift easily with no clutch while braking or do you have to use the clutch? I suppose the latter because the box would be loaded up under braking?

Also, how does power level affect RPM/speed ratio in any way? - Unless of course your clutch is slipping!

Link to comment
Share on other sites

Can you downshift easily with no clutch while braking or do you have to use the clutch? I suppose the latter because the box would be loaded up under braking?

Also, how does power level affect RPM/speed ratio in any way? - Unless of course your clutch is slipping!

No, you can down shift without the clutch if you heel toe correctly and match the revs. The slight blip of the throttle counteracts the deceleration force to unload the dogs to allow it come out of gear. As you go through neutral, the throttle blip will speed up the gearbox internals to the same speed to allow them to engage without clunking, banging or simply not going in.

The way a dog box work vs a synchro is very different.

Power affects it slightly. More power means more force. More force means more output. More output means more speed.

For example, at one power level i got 10kph/1000rpm in 1st gear. After adding 100awkw and changing nothing else, i get just over 12kph/1000rpm in 1st gear now. So it isnt a huge factor in terms of how it affects your speed. tyre size and final drive would make more noticeable differences.

Link to comment
Share on other sites

No, you can down shift without the clutch if you heel toe correctly and match the revs. The slight blip of the throttle counteracts the deceleration force to unload the dogs to allow it come out of gear. As you go through neutral, the throttle blip will speed up the gearbox internals to the same speed to allow them to engage without clunking, banging or simply not going in.

The way a dog box work vs a synchro is very different.

Power affects it slightly. More power means more force. More force means more output. More output means more speed.

For example, at one power level i got 10kph/1000rpm in 1st gear. After adding 100awkw and changing nothing else, i get just over 12kph/1000rpm in 1st gear now. So it isnt a huge factor in terms of how it affects your speed. tyre size and final drive would make more noticeable differences.

Cool that makes sense. So to downshift without the clutch you would be braking into the corner, jab and hold the throttle with your heel and then swiftly put it into the next gear?

I understand the difference between how they work, just wondering what driving styles work and don't work.

I believe you can drive a dog box like a synchro box, ie) clutched shifts etc. but you must be affirmative with the gear changes. (See PPG how to drive a dogbox video)

However, you obviously can't drive a synchro box like a dog box, as the synchros won't let the shifter slam between gears without being rev matched.

I still disagree with your statement that more power = more speed unless you have some technical description.

Everything is meshed in a manual box, so assuming there is no slippage the crankshaft speed is locked to the wheel speed.

Wheel rotations per minute is always going to be equal to something like =

RPM x clutch slippage factor / gear ratio / final drive ratio

There is no way I can see that more power can produce a higher wheel rotational speed at a given RPM.

Additionally, you are not using any more power to maintain 10k/1000rpm now than you did before, the amount of power used would be exactly the same, but the throttle position might be different to maintain the same speed.

Edited by Jazzadub
Link to comment
Share on other sites

Straight cut dog box will be annoying on a street car - unless you love the loud sound of the whining gears. Not sure how loud the whine is on the straight cut PPG, but the Trust straight cut dog box is very loud. Doesn't help if you have a quiet exhaust either. Let me know when you meet up to test drive the PPG (if you haven't already) as I would like to compare and might swap to a PPG and leave the Trust to the race car.

Link to comment
Share on other sites

Straight cut dog box will be annoying on a street car - unless you love the loud sound of the whining gears. Not sure how loud the whine is on the straight cut PPG, but the Trust straight cut dog box is very loud. Doesn't help if you have a quiet exhaust either. Let me know when you meet up to test drive the PPG (if you haven't already) as I would like to compare and might swap to a PPG and leave the Trust to the race car.

Charlie, unless you want straight cut 1-5 (straight cut 5th would get annoying on the freeway), PPG only do a helical 1-4 helical dog with a synchro 5th (standard ratio if you wish).

I still haven't met up with Sime, is the helical dog something you're interested in?

Link to comment
Share on other sites

Unfortunately, I don't think the helical will handle what I have to throw at it. The straight cut box will end up costing close to what an OS Giken sequential will (Well, close enough to make the OS Giken Seq. a viable option) The OS G is also helical cut and can handle 1500hp.

Link to comment
Share on other sites

Unless you need dog 5th, helical dog 1st-4th is the best for the street because it doesn't make any noise.

After the first couple of months hating life that you just blew a shit load of money on something noisy you can't drive, come and talk to me once that's over and let me hear how you'll never want a synchro box again. Ever.

They are the ultimate.

Link to comment
Share on other sites

Unless you need dog 5th, helical dog 1st-4th is the best for the street because it doesn't make any noise.

After the first couple of months hating life that you just blew a shit load of money on something noisy you can't drive, come and talk to me once that's over and let me hear how you'll never want a synchro box again. Ever.

They are the ultimate.

That's what I keep hearing!

What's in yours, Paul? 1-4 helical or 1-5 straight cut? I've seen a few of your vids, particularly at Coota. You're not nice to them at all!

Link to comment
Share on other sites

Helical dog 1-4. I broke a selector after over 30,000k's, and replaced a few bits from it last year, that was 6 years worth of abuse that you've seen on those videos. It's the only way the car gets driven, and I might add that both the guys who work on the car had been learning to drive on it as well.

When I broke the selector it was partially my fault, but most of the wear would have been caused during the initial period of me getting it together.
It does take time to learn though, you can't just jump in one and think you're Fangio, it will bite you in the arse and if you are offered a test drive, you're wasting your time unless someone experienced is in the driver seat.

Link to comment
Share on other sites

It's stock, I used to worry about busting it but I did the Snowy Mountains 1000 and had 5 passes into 5th, certainly reminds you how much you hate synchros when you go to shift in 5th fast.

Link to comment
Share on other sites

  • 2 months later...
  • 2 weeks later...

After months and months of research, I've decided to go the OS88. Went for a drive in one and it was awesome. Quiet in gear, bit of clunking between gears but who cares about that, 4 choices of ratios and 6 speed. It also bolts straight into a R33 GTR so no shaft/transfer case changes.

It won't happen this year, but it'll happen. :)

Link to comment
Share on other sites

Won't that be a bitch to drive on the street though?

Meh, I'll live. It's just different.

It ain't a daily, when I take it out I'm giving it a hard time.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Latest Posts

    • Check your FPCM. What happens if you bypass it? The ECU will bypass it during prime + initial start, then the FPCM kicks in and slows the pump down.
    • Did you pay using a credit card? If so, possible you could do a charge back?
    • Hey guys, I did a smoke test this week chasing vacuum leaks and found two leaks which I fixed up... Now having a weird issue where it starts and at idle after a few seconds the fuel pressure suddenly goes to 0 and stalls.. if I blip the throttle, it will regain pressure and keep going though. I put a new fuel filter on and drained the old fuel and put new fuel in but maybe thats stirred up some crap in the fuel tank and blocked the intake or something??? Any other ideas? FPR stuffed? EDIT: Also, when it stalls, the pump primes and pressure goes back up and it starts again as per normal and happens all over again.
    • Absolute best bang for the buck I've ever owned. Stock they had somewhere around 550-600hp, a pulley, intake and exhaust later I was at 800. Absolute torque monster and blast to drive. 
    • I don't have to globe holders because they disappeared with the indicator assembly. I cut off the car side connector and replaced with spade connectors (it used foul up with moist dust). So GTR globe holders might work. I found a complete assembly on eBay, but they want $390!!!! I purchased a replacement pair of smoked lens assemblies, but they don't come with the globe holders and wires.
×
×
  • Create New...