70 replies to this topic

[86psi]

i thought the evo 3 rods were only good for 21psi read that somewhere hence why i havent gone past that. but then again with the extra cooling properties of running e85 maybe it can be pushed further

[DOUGMO]

21psi on what turbo?

its the actual torque as said by others that will break the rods/rod bolts, and also the revs that the torque is made at.

I had stock rods crack tested,shot peened, brass bushed in the little end and fitted with arp rod
bolts and smashed the rods into dust on around 20 psi on a td05 20g using united 100 fuel
which is 10% ethanol. My car was making 270kw and 460nm of torque.
I did not rev the car hard at all. but it was a 2.3 which will load the rods more.

As Scott also said, it seems guys with road cars get away with a lot more being normally only short bursts of power
in the lower gears that the engines see.

Something to think about anyway,

[86psi]

i been running 21psi with a tdo5h/20g made 211kw on a mainline dyno forget what torque it made but i remember it was a pretty high number at the time that people thought was wrong. Ive been running on that tune since 2007, thats prob about 40 runs down the strip 50 thou kms of spirited street driving and a motorkhana event.

are you sure its actually the torque that kills the rods and not the heat ? only say this as i remember the old owner of my car telling me when apc tuned it they ran a heat gun on the block to make sure the rods wernt heating up too much which is why it got pushed to 21psi

[DOUGMO]

Im very sure

[BMGTZ]

sorry to get off the topic but ..the heat gun.....I am intrigued by that. tell me how it would be able to measure anything but the block?and what the block temperature relates to in terms of the rod

Edited by BMGTZ, 26 June 2011 - 02:54 PM.

[86psi]

point the heat gun at the block where the rods are and should give an idea of the heat generated from inside im guessing thats what they were doin stuffs me just what i was told. I guess you wouldnt know unless you tried it to see what temp differances there are between idle and load conditions

[(2much)]

sorry for OT, but im a bit lost about this temp thing, and if it's a measure, what temp can rods handle?

[86psi]

Well I'm guessing it all depends if it gets too the lowest critical temperature which is the temp needed for the grain structure in the steel to change.

[blackvr]

Im very sure

I am very sure as well Dougmo !! As well, ( I have been doing dyno work for 20 years), the logic of a heat gun measuring con rod temperatures from the outside sounds a bit suss...

[lozza]

I am very sure as well Dougmo !! As well, ( I have been doing dyno work for 20 years), the logic of a heat gun measuring con rod temperatures from the outside sounds a bit suss...

yeh it sounds like a lot of bull to me. Heat is generated mainly from combustion and less so from friction. Con rods don't produce heat unless you've spun a bearing. And even then it won't do any good because it is already too late!

[ENGINR]

i remember the old owner of my car telling me when apc tuned it they ran a heat gun on the block to make sure the rods wernt heating up too much which is why it got pushed to 21psi

This has made me laugh - I needed a laugh this morning. Thanks!!

[86psi]

ohwell aslong as you got a laugh out of it lol

[robevo]

Ive been running e85 for a year now and all is good so far, Its a much cleaner fuel for the environment too
Im breaking 4th gear on the dyno now

[EV0300]

Bit of a revival, but im planning on switching to e85 in the next month or two. reading this now though im abit worried about my rods/rod bolts.

will my engine last with the extra torque, im looking for about 230kw. should i be looking into arp rod bolts?

[DOUGMO]

you can tune around it so the torque comes on later but that kind of defeats the purpose.

 

arp rod bolts need the rod to be machined to suit on early 4gs.  220-230 would be borderline imo.

 

what turbo?

[EV0300]

18g its making about 200 at the moment :/ i do have e9 internals to put in it but thats another step up in cost to get them put in bores checked etc..

[ENGINR]

From my experience, worry more about your gearbox than your engine!

[EV0300]

^ that was my second concern.. though im not very rough with the gearbox very often anymore.

[DOUGMO]

From my experience, worry more about your gearbox than your engine!

7 bolt rods will die before you make enough power to trouble the driveline

[evo-gsr]

Build the engine and go for gold!!