Light weight Engine internals?
Turbo Mini Forums

Hi,
I was wondering does anyone use a lightened crank(wedged) or lightened rods in their turbo motors? I realse they improve acceleration by reducing inertia, rotating mass etc. But does this leave you with a lack of strength in these areas due to the extra loads involved with forced induction? I have these polished rods to go into the turbo motor, so I was thinking about lightening them aswell.

Cheers,
Gavin. :)

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I'm one of the last people to lighten anything - BUT I'd DEFINATELY be doing something with them rods!!!

A+ rods are over-engineered. The weight saving can be made by trimming off the corners which can be the starting point of failures. No need for anything more fancy, even for the most beastly motors... as far as I know of course!

I donated, but somehow didn't get the label! :(

What I've done previously to A rods, ( Whis are stronger than A+ by the way) is to hacksaw the big ugly square bit of metal on the bottom. This alone weighs in at approx 25 grammes. I then remove some more metal and smooth the surface as per porting heads . I use the thickness of the A+ big end cap as a guide.

Rememeber, after having lightened and polished the rods, they will "move " slightly. If it is a serious build, have the rods straightened, and the big ends checked for ovality and resized if necessary. My experience is that A rods don't tend to go oval compared to the A+ ones which always need a good hone!

Edited by Vegard on 17th Feb, 2006.

Mines wedged and bladed

i didnt choose this, it was already done but hope it works well. should fine out in the next month or so.

Blading sucks!

Edited by Vegard on 17th Feb, 2006.

dunno whats been done to mine looks good condition so that will do me :)

i think me having cooper s rods creates more inertia? because of the extra weight over A and A+ ??

S rods cannot be heavier than metro surely,

carl

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I was all for having a fancy state of the art fancy crank (this was for my 1380 NA race motor), but after a chat with Simon at Morspeed, he recommended that if I had some A+ rods fully lightened and balanced, coupled with an A+ wedged and hardened crank, Id pretty much be sussed. He wasnt a fan of blading as it reduced the counterbalance.

Got some pics of the bits he did for me somewhere, can post them up if anyone wants.

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

Show thie pics please.

http://www.rabdunn.co.uk/

Click on them to get them bigger..

Some of the rods:





Some of the crank:

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

*edit* didnt mean to post again!!

Edited by joeybaby83 on 18th Feb, 2006.

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

OK mines NA but the crank is X drilled, wedged, bladed and the big end pins are drilled to gain counter balance against the blading. Its very light and lets me rev to 9400 fairly regularly and over 10,000 on a flat gearshift. IMO strength is not compromised, but some peeps like a heavier crank.
Paul

I seriously doubt it!

i like the idea of backdrilling to increase counterbalance, but it wasnt readily available when i got my crank.

Concerning crossdrilling the big ends, I rev the bollocks off my engines, had the big ends go once, but that was purely through oil starvation (had no CPU) on a massive right hander. So in the next year i will be able to confirm if crossdrilling is a bunch of arse or not LOL

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

paul out of interest ,whick tacho do you use??.

carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Hi,
Thanks for the replys. I've got to lighten them rods then, due to the maths professor and Dave, LOL! I'll get the crank wedged and hardened. Tuftride or nitride, or are they the same thing?
Also, excuse my ignorance, whats the numbers on the A and A+ rods, please?
Cheers,
Gavin. :)

Edited by Bat on 18th Feb, 2006.

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i'm big on lightweight internals ,right down to special allumiium alloy big end bolts, serious shit you know,

carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Carl, you mean you manufacture them yourself?
Mark

I donated, but somehow didn't get the label! :(

no ,i'm joking .sorry if i got your hopes up,lol
carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Fastcarl, Its not pulling that it goes over 10,000. I change up the gear at 8,500 -9,000. It goes over 10 while the clutch is in and my right foot is still planted.
I should have a rev limiter but I theorise that it would wet the plugs and not give full potential while they are drying so I choose to risk blowing the engine.
I sometimes rev to around 9 - 9,500 to overtake Ferraris
Paul

I seriously doubt it!

LOL

I seriously doubt it!

thats not what bi asked you ,what your tacho says is not necessarily accurate depending on make,
we must not forget needle carry , a long time back there was an article in ccc on tacho testing.
i cannot remember exactly what the results were but i know TIM, ELLIOT and STACK,were in .
but about 6 of the popul;ar names were tested, with supprising results.
i remember that TIM were the second most accurate at something like 3% overead, the rest were progressively worse,
only STACK were 100% perfect with excellent damping.
the prob with tachos is the faster the engine speeds the harder it is for then to count the sparks,there fore more error higher up the range.
i wish i still had the mag from all those years ago , maybe 12 to 14 years ago, .

you know mwe better than to have a dig at you but if you ever want to borror one of mine and wire it in you can. then you will know exactly .
proper bar hp whenn you state the make and model of tacho used ,at least to those who know the difference,lol.
so what tacho are you using????
carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Youre quite right Carl, I forgot to put that bit in.
I use a 0 - 10 Smiths.
OK Smiths is cheap but adjustable to match rolling road readings at 8 - 10 thousand revs. I do believe there will be quite some "needle throw" but it goes right round to where 14,000 would be so its gonna be somewhere near 10,000+ probably.
Even if thats not right I believe 9,000+ whilst flat out is 95% accurate.
Paul

I seriously doubt it!

At 9000 revs I reckon you guys are bloody brave to be able to even look at the rev counter, I would be wincing and squinting my eyes waiting for the KER-BOOM and the sound of shrapnel hitting the underside of the car!!!





(Only jesting, I know you both have fully prepared proper engines)