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 Post subject: Re: ECU chip or standalone on a 1300 NA high compression
PostPosted: Fri Aug 04, 2017 8:34 am 
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Location: Wellington
All you ever might want to know about the topic.

viewtopic.php?f=7&t=49907

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 Post subject: Re: ECU chip or standalone on a 1300 NA high compression
PostPosted: Sat Aug 05, 2017 7:40 pm 
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Joined: Tue Feb 23, 2016 5:38 am
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Location: Christchurch
That's a good article and well explained but I don't believe it's the full story.

In a production engine, like the G13B in a mk3 GTi, there's a few key reasons why the manufacturer will use an external dampener:

The first will be cost. It's easier and cheaper to balance externally than to attempt to fully internally balance the crank, rods, pistons etc.
The second is that the car will seem smoother to drive. The dampener helps absorb the accelerations each time a piston fires, that's the idea of the rubber cushion between the two layers, making the car seem smoother at idle and smoother to drive.
The third would be service life. The dampener helps reduce the stress on the items driven from the crank like oil pumps.

The manufacturer won't be aiming to control dangerous harmonics at very high revs.

For a race or rally engine you need to decide how relevant some of this is. You'll almost certainly fully internally balance the crank. The engine won't be built for a long service life. You'll want to underdrive the ancillaries. The risk of oil pump failure in a G13B is probably minimal given how it's driven. You'll attach the flywheel with ARP or similar fasteners so the risk of failure is minimal. With cams a smooth idle won't be a priority. You probably won't be aiming for numbers north of 9500 rpm where a dampener would be required.


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 Post subject: Re: ECU chip or standalone on a 1300 NA high compression
PostPosted: Mon Aug 07, 2017 4:33 am 
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Location: NZ
Holy Christ....using my supreme intellect and ability to absorb information like a sponge I totally got it after this statement Howsie...."Technically, 'the primary purpose of a harmonic damper is to cancel out third harmonic distortion by using intermodulation between the second harmonic and the fundamental in the space charge regions of the triodes" I figured that it might have something to do with the 1.21 gigawatt spurling bearing but I could be wrong.... :shock: lol. Thanks for the link it was interesting to read!

I am taking the crank, pulley and flywheel in for balancing. I'm going to use the rods I bought as they are factory balanced in total weight and end for end....getting that done to the stock rods even though they are totally sufficient for the job makes using the max speeding rods viable. I'm getting the honduh Pistons from Mike in Canada. I'll ask if he balances them. I'm assuming as he machines them for the G13b that he would match them. That woukd give me a balanced engine. I imagine we would be lucking to race it for 2000 k's in its life time with us. I hear Derek's words of advice re cavitation of the water pump. I guess underdriving that is possible but over charging is an issue too....most of its life it will be revving past 5000 and up to 8600. I think I'll take the risk of removing the HB.

Meantime I bought these off Joel in the states. Got another 4.389 FD. The rest are new parts. Yes they are Chinese....from holding them they look the part. Time will tell if they can take the thrashing. They are made to Japanese specs. The genuine stuff is so damn expensive and I have a hoist....plus a spare box.....so I'm going to use my best genuine gears in the good box and test these in the spare box. I'll report back.


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 Post subject: Re: ECU chip or standalone on a 1300 NA high compression
PostPosted: Mon Aug 07, 2017 4:39 am 
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Location: NZ
Got these too....but the lads have told me I could kill the engine torque with the size of the primaries. Was going to mod the end flange but the primaries are 1.75". However....all is not lost. Apparently the secondaries can be 1.75"? I could utilise that part and throw the top end on trade me. Cheap enough.


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 Post subject: Re: ECU chip or standalone on a 1300 NA high compression
PostPosted: Wed Aug 09, 2017 6:05 pm 
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Location: Christchurch
I'm running a 4 into 1 with 1.5 primaries so 1.75 does sound big.


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 Post subject: Re: ECU chip or standalone on a 1300 NA high compression
PostPosted: Wed Aug 09, 2017 9:55 pm 
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Joined: Mon Oct 12, 2015 11:30 am
Posts: 69
Location: Wellington
swift12 wrote:
Holy Christ....using my supreme intellect and ability to absorb information like a sponge I totally got it after this statement Howsie...."Technically, 'the primary purpose of a harmonic damper is to cancel out third harmonic distortion by using intermodulation between the second harmonic and the fundamental in the space charge regions of the triodes" I figured that it might have something to do with the 1.21 gigawatt spurling bearing but I could be wrong.... :shock: lol. Thanks for the link it was interesting to read!

I am taking the crank, pulley and flywheel in for balancing. I'm going to use the rods I bought as they are factory balanced in total weight and end for end....getting that done to the stock rods even though they are totally sufficient for the job makes using the max speeding rods viable. I'm getting the honduh Pistons from Mike in Canada. I'll ask if he balances them. I'm assuming as he machines them for the G13b that he would match them. That woukd give me a balanced engine. I imagine we would be lucking to race it for 2000 k's in its life time with us. I hear Derek's words of advice re cavitation of the water pump. I guess underdriving that is possible but over charging is an issue too....most of its life it will be revving past 5000 and up to 8600. I think I'll take the risk of removing the HB.

Meantime I bought these off Joel in the states. Got another 4.389 FD. The rest are new parts. Yes they are Chinese....from holding them they look the part. Time will tell if they can take the thrashing. They are made to Japanese specs. The genuine stuff is so damn expensive and I have a hoist....plus a spare box.....so I'm going to use my best genuine gears in the good box and test these in the spare box. I'll report back.


Darn, your workshop sounds like so much fun. Yea, its always the kilojon combobulator in that situation, it is easily overlooked.

Re: HB - if you are balancing internally anyway, then changing the HB would be quite safe I assume.

Run an underdrive pulley and a clutch pulley on the alternator. (oops, did I give you something else to learn about???)
Have fun with gearbox, I'm sure it will be ok as a secondary box for a N/A.
1.75" primaries might be too big, I suppose you will only know if you try it.

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 Post subject: Re: ECU chip or standalone on a 1300 NA high compression
PostPosted: Wed Aug 09, 2017 10:11 pm 
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Joined: Mon Dec 19, 2016 10:40 am
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Location: NZ
Well first issue....the low speed hub is 35 tooth.....mine is 36. Obviously there are different reverse ratios among model. Why? Lol. I guess that means every reverse gear would have to be different....the input shaft as well as the idler. Stuff it.....at least the 2nd gear is the same. Haven't checked the high speed hub yet. Picked up an APV MLS head gasket. will that work with the 75mm Honda Pistons? It's for a 76mm bore but reading in the forum suggests it's fine to use. I guess 20 thou all round the cylinder makes bugger all difference.

Got to get another trip to the states for the parts. They won't be ready by the time I go to Houston....bugger! :(

Oh well....build gearboxes, put the suspension back together. Fit the new brakes. Tidy up the dash. Tidy up the engine bay. Plenty to do to keep busy while waiting.


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 Post subject: Re: ECU chip or standalone on a 1300 NA high compression
PostPosted: Mon Aug 14, 2017 7:32 am 
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Joined: Mon Dec 19, 2016 10:40 am
Posts: 98
Location: NZ
working on the low speed hub issue.. seems like the 35 tooth reverse low speed hubs are those ones in the states like chevy sprints and geo metros etc. I've given him two part numbers....one is the part number of the hub he has given me and the other lists the part number of the AA34S and other models. Joel said he has been sent the wrong part before so we are hoping its the "other" hub that we need...ie 36 teeth. Im not paying hundreds and hundreds for a genuine suzuki hub if these things will work so Ill wait to see what comes up. Meantime I have at least one good low speed hub.

In case you were wondering...35 teeth on the reverse gear on the low speed hub matches with 12 teeth on the input shaft...where as we are 36 and 11. I have no idea about the idler gear but obviously there is a change of position of the idler in those boxes to suit...


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