Karlos G

iTrader: (4)

What BHP/Torque were you running, and what was your rev limiter set at?

I know what everyone says which is 220bhp-250bhp but I want actual experiences, so please only people that have actually had it happen, or know someone personally that it has happened to!!
I know the bolts are suposed to be a weak point to so lets here about anyone that has had them let go to!

Trying to get a definitive idea of what they can actually take...

Cheers!

GaryEvo

ive seen bent ones in tonyturbo's car

andy130

iTrader: (2)

it depends on boost aswel

Karlos G

iTrader: (4)

What was his spec Gary, BHP/Torque?
Did you look at this thread thinking 'Oh no Karl hasnt managed to snap a rod as well now?" LOL
No it doesnt, boost is relative.

Rick

compression pressure is a major contributor, which tends to be directly related to boost. I have bent 3, and been in car which has snapped one. Power and torque were around the 210 mark on both cars.

Rick

Karlos G

iTrader: (4)

Yeah but as I said boost pressure is relative Rick, it is not a direct representation of the volume of air in the chambers is it............
For example Stock CVH engine @ 14psi will have 'X' amount of air in the chambers and produce 'X' bhp, but a CVH with low comp, oversize pistons, big valve ported head, and a T34 @ 14psi will have 'XXXXXX' volume of air in the chambers and produce 'XXXXXX' bhp!!
Which is why I did not ask for boost pressure becasue it's relative.....
But BHP and Torque will give a direct representation of the force exerted on the rods.

I am shocked that around 210 mark has bent and snapped rods!!! WTF happened, water in the chambers??!! LOL
Or was it sustained high RPM's?

tooly80

one of mine bent then snapped when the bore melted to the piston and jammed it up.the pipe to the actuator came off so it was running unlimited boost.

Charlie Chalk

iTrader: (1)

My friends just put one through a block and he was running 20psi, unknown power!

Car was a CVH 1600 turbo on R5gtt carb, T3 stg2 turbo.

Karlos G

iTrader: (4)

Nasty!!
Rod snapped or big end bolts let go?

Charlie Chalk

iTrader: (1)

Unsure tbh mate, Blocks out now and waiting to be inspected, But you could see a rod poking though the hole when it was in the car...

tooly80

just the rod snapped the bolts still stayed in,tore a hole in the bore then come through the front of the bloke.gutting.

BRAM

iTrader: (1)

My brother snapped a rod 2 days after getting his car set up off jano oddkidd, Jano said it was about 260 bhp but never had it on the rollers. He was running about 25 psi not 100% tho because the boost guage only went to 20psi but the needle was going past that. The car felt awsome for 2 days ha ha

Karlos G

iTrader: (4)

hmmm...... seems that the rods are actually quite delicate!!!

jonny s2

iTrader: (12)

wouldnt shot peening help if your on a budget

Karlos G

iTrader: (4)

I was thinking that Jonny, would be interesting to know how much stronger it actually makes them and what the cost would be!

muz

From what I Was told, shot peening doesn't actually make the rods any stronger it just removes and polishes tiny imperfections which could lead to fractures as the rod will break across the weakest point. Steel rods are cheap enough these days Karl tbh.

Back to the subject, I'm sure Gav has just had a rod let go on his at about 200 brake but he was using a 50 shot of NOS

jonny s2

iTrader: (12)

you could send them off for crack testing,im sure tom scarletts s1 had standard rods and were messed with abit he was doing way over the 300 mark,im sure if you dont do big revs they will last longer,but as said you can get steel rods for cheap now due to more an more people buying

BRAM

iTrader: (1)

my brothers were shot penned and they still snapped he has gone steel now

Rick

Bent rods were actually due to head gasket issues. Snapped rod was around 70mph in 5th just coming on boost.

You'll find that providing it's not a 2 litre, the low down torque changes very little regardless of engine mods. On a dyno day years ago, my full on all steel NMS big valve head with cossie t3 did 210hp at 11psi, with around 165lb of torque, a friends did 200hp, 200lb at 18psi on a std engine/turbo.

Rick

jonny s2

iTrader: (12)

karlos sent you a pm bud

Karlos G

iTrader: (4)

Cheers for all the input fella's it seems that Rods are a bit of a lottery then really, so as my engine is in bits it would be silly not to go Steel H section.............. more money and delays!

clarke5700

depends on what power you are going for realy?

Karlos G

iTrader: (4)

There are people snapping them at 210bhp with similair torque and i will be well over that! Estimate 220-240bhp my Stage 2 T3 being the limiting factor.
So i'm not going to risk another rebuild because I didnt take the opportunity to upgrade the rods, it's just not worth it!

jammerrs

sounds a good idea to me mate, no point gambelling more time off the road

have to got uprated pistons btw?

jonny s2

iTrader: (12)

karlos let me know the outcome of the rods

rstdave

iTrader: (3)

Mine ran 245bhp@1.5bar boost and ran like this for 2 years, trackdays/pod/brunters the lot, with arp bolts being the only mod. When the bottom end finally let go earlier this year i was expecting it to be a bent rod as it happened when i was holding it off the limiter, but turned out to be a shattered piston skirt! I was surprised at how well it lasted and had it not been for the AE pistons i used it would be still in the car now!

Karlos G

iTrader: (4)

I have but they are up for sale as i want to stay standard CR and Mahles are good for a proven 300bhp so that well over what I will be running.

Will do cheers Jonny!

Yeah think a bit of a lottery then, some may have more or less casting imperfections than others I guess.

Rick

with a piston, there is at least a chance it won't ruin your whole bottom end.

rstdave

iTrader: (3)

Think it probably is yeah....mine didn't actually snap a rod though so i can't complain about them really!

jonny s2

iTrader: (12)

its more the revs that kill the rods

ro33

20 psi is not too much pressure for conrods stock
How much is the maximum pressure that hold ?

haz87

5 year old post...

ro33

That will be better to open another post ?