Jason Posted November 6, 2007 Report Share Posted November 6, 2007 I'm reading alot of conflicting stuff regarding straight cut gears. Are they any stronger?? because I'm tossing up between a W box and a set of TRD straight cuts, but its starting to look there is no strength benefit regarding SC. :evil: Quote Link to comment Share on other sites More sharing options...
irokin Posted November 6, 2007 Report Share Posted November 6, 2007 Even if a straight cut gearset is a T50 is stronger than a W50 I think you'll be beating your head against the window with the amount of noise. If you're going to street it just stick with a helical. There is a reason hollinger uses straight cut gears in their $30,000+ gearboxes....and I'm pretty sure its not because they're weaker. Quote Link to comment Share on other sites More sharing options...
slapper Posted November 6, 2007 Report Share Posted November 6, 2007 yes, straight cut is stronger. YES, straight cut is noisier (holy crap noisier) - half the noise you hear in the group A in-car cameras is the gearbox. yes, they demmand more proficiency from the driver - you need to get it all the way into gear, or don't bother. Helical gears tend to "pull themselves together" when partially meshed ... straight cut gears will just tear the ends off the teeth. Daily driver, street ... other people sometimes drive your car - helical. If you want to be able to listen to the radio - helical :evil: What are you putting the transmission behind that strength is a consideration? cheers, Slapper Quote Link to comment Share on other sites More sharing options...
Taz_Rx Posted November 6, 2007 Report Share Posted November 6, 2007 yes, they demmand more proficiency from the driver - you need to get it all the way into gear, or don't bother. Helical gears tend to "pull themselves together" when partially meshed ... straight cut gears will just tear the ends off the teeth. Unless you have a straight cut dog box!! :evil: Quote Link to comment Share on other sites More sharing options...
slapper Posted November 7, 2007 Report Share Posted November 7, 2007 (edited) wow ... I'm going to retract everything I said (except for the bit about the noise) with the statement "apparently I don't know enough to comment" !! I've just done a little reading on the 'net (and don't have time to do more at the moment) and ... Apparently, straight and helical cut are available in dog-box or synchro form. Apparently, straight cut results in no thrust stresses whereas helical does. Helical is quieter. Straight may be more efficient due to the lack of thrust forces - no rotational forces are converted to thrust ... Arguments abound in both directions about which is stronger - apparently, straight seems to allow stronger designs, but these are not necessarily realised. Straight cut dog-box is the race car choice - faster gearchanges, but more technique required from the driver. Helical is the usual street choice due purely and simply to the noise. Here's a cut-and-paste from (2005 post) another web group - it's a nice summary. The poster is from Andrewtech Automotive who specialise in Subaru shite on the US East Coast: Straight Cut Gearset The Straight Cut gear design incorporating our PPG distinctive tooth profile provides even more strength than our already ultra reliable helically cut gearsets. One of our more popular items ... the Subaru WRX straight cut set can be found in vehicles with over 600hp. A far cry from the standard power output from factory and certainly a power level that needs a gear box of phenomenal strength to get power to the ground without failure. Straight cut gearsets are relatively noisy in operation and have an inherent whine to them. This is due to the meshing of the teeth when the gears are rotating. The meshing of straight cut teeth gives total contact along the tooth at all times which gives the straight cut tooth its added strength over the helically cut tooth . Helically Cut Gearset. PPG helically cut gearsets are our most popular product. Mainly used to transmit extreme power to the road in highly modified street cars. They are usually purchased by those wanting less gear noise than a Straight Cut gearset. Our Helical sets do produce slightly more gear noise than a standard factory gearset as a result of a purely motor sport based gear design which makes necessary compromises in regards to gear noise, to achieve uncompromised strength. Synchromesh Engagement (Synchro ‘box) PPG Synchromesh Gearsets enable factory style gear selection to be incorporated into your Helical or Straight Cut Gearbox. The Synchro’ Box is mainly used for street applications. At PPG we make the Synchromesh rings and hubs considerably stronger than factory components and incorporate our high quality materials and heat treating processes into the finished product ensuring durability you can rely upon for years to come. Dog Engagement (Dog ‘box) Essentially a “race only” style of gear engagement, this has become more and more popular for highly modified street cars. Dog Engagement gear selection is available on either Helical or Straight cut PPG Gearsets for a variety of applications. And a combination of Dog and Synchro’ is available on our Subaru sets. Providing fast, positive gear selection, with or without the use of clutch. The PPG Dog Engagement gear sets are undoubtedly the strongest and most “user friendly” on the market. However it should be pointed out that Dog Engagement Gearsets require fast, firm gear selection and are quite noisy on each gear change cheers, Slapper Edited November 7, 2007 by slapper Quote Link to comment Share on other sites More sharing options...
Taz_Rx Posted November 7, 2007 Report Share Posted November 7, 2007 Yeah as far as I know the main difference with a dog box is the way you can point it at a gear, and then the gearbox pulls it into mesh. Sorta get it half way and it snaps in. This is why the driver needs to be experience, because if you accidently point it more towards 1st when you really want 3rd it'll pull itself into 1st and give you a "dog" of a gear change. :evil: Quote Link to comment Share on other sites More sharing options...
styler Posted November 7, 2007 Report Share Posted November 7, 2007 before you compare the two, have you checked out how much straight cut gearsets cost? plus installation... and the noise is incredible! Quote Link to comment Share on other sites More sharing options...
Taz_Rx Posted November 7, 2007 Report Share Posted November 7, 2007 http://youtube.com/watch?v=Fgy9vc4rf90 Heres a good example of the noise, mind you this is a very close ratio box. This is actually an awesome vid, this guy can drive!!! :evil: and yes...the are geminis! well opel cadets anyway. Quote Link to comment Share on other sites More sharing options...
fusion Posted November 7, 2007 Report Share Posted November 7, 2007 http://youtube.com/watch?v=Fgy9vc4rf90 Heres a good example of the noise, mind you this is a very close ratio box. This is actually an awesome vid, this guy can drive!!! :( :evil: Thats some nice driving Quote Link to comment Share on other sites More sharing options...
KRASHDOG Posted November 7, 2007 Report Share Posted November 7, 2007 YEAH THATS NOBEINO... MAN THAT BMW IS LOUD!!!!!!!!!!!!!!!!!!!!!!!!!!! JAYSON Quote Link to comment Share on other sites More sharing options...
dookie Posted November 7, 2007 Report Share Posted November 7, 2007 ok I'm deaf now :evil: thats some sick drivin! Quote Link to comment Share on other sites More sharing options...
Jason Posted November 7, 2007 Author Report Share Posted November 7, 2007 yes they are loud but the rolla is only going to be used for driving nothing more... TRD stright cut is aound the 2g mark. Soz a little drunjkrigtt now just got back from my final exam :evil: Quote Link to comment Share on other sites More sharing options...
camerondownunder88 Posted November 7, 2007 Report Share Posted November 7, 2007 Drunk at 2pm of a Wed arvo Jason..GOOD WORK :evil: Wait till Friday everyone..LOL With straight cut gears they are shorter but louder as everyone else has said so that is the main point. But this is left of field etc not sure if it is correct. Now superchargers spin amazingly fast to make the little boost they do. Now most of them (SC14 included) run straight cut gears I know they move air and when you do that it makes noise. But the whine from the super charger is that partly concerned with the straight cut gears in it? Would this play a part in that sweet noise? Cam Quote Link to comment Share on other sites More sharing options...
irokin Posted November 7, 2007 Report Share Posted November 7, 2007 yes, they demmand more proficiency from the driver - you need to get it all the way into gear, or don't bother. Helical gears tend to "pull themselves together" when partially meshed ... straight cut gears will just tear the ends off the teeth. Slapper I think you're confusing the gear engagement (syncro/dog) with the gears themselves. The two gears are actually never become disconnected. They are always meshing even if that gear isn't being used. The syncro or dog locks that gear to the shaft thus selecting the gear. I'm pretty crap at explaining it however... You can have helical dog boxes and straight cut syncro boxes. Just because you have straight cut gears does not mean you have to have a dog engagement (but thats usually the way people go. Racing means more strength needed and fastest possible shifts which means straight cut gears and dog engagement). Jason if you intend to spend much/any time on the street avoid the straight cut. I know I said it in a previous post...but just so you're 100% clear with my view :evil: $2k is very cheap for any aftermarket gearset. I would be questioning its quality if its new? OS Giken 1st to 3rd gearsets for silvias start at ~$1.7k ex-japan. Full gear sets start at more like $3k without any heavy duty options. Good gearset manufacturers (PPG, PAR, etc) start at ~$5k for syncro boxes and ~$8-9k for a full blown straight cut dog box. Also if its a dog engagement gearset (I doubt it for that price) be prepared to service it every 5000km or so. Replace damaged dogs, refinish balk rings, replace anything else that needs it and other shit like that. They are very high maintenance gearboxes. I've done probably well over 100hrs of research on gearboxes and gearsets for my car as I'm about to start grenading gearboxes myself :( and Id like to get it right the first time considering the cost of the bloody things Quote Link to comment Share on other sites More sharing options...
Taz_Rx Posted November 7, 2007 Report Share Posted November 7, 2007 It pretty much is the cool noise! When you see a big blown V8 with a whine as it lumps over, it not the charger itself your hearing,...its the 3 inch gilmer drive belt infront of it! :evil: Quote Link to comment Share on other sites More sharing options...
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