Some food for thought

With the following information, the maximum force exerted on the conrod seems to work out as follows:

(CP piston and Eagle conrod data shown in brackets)

1.314kg (1.022kg) - Conrod, piston, rings, pin, bolts and bearing weight
137.96mm - rod length (Eagle is a touch shorter but ignored for clarity)
86.0mm - piston stroke

RPM . . Force (Tonnes)
1000 - 0.08 (0.06)
4000 - 1.33 (1.03)
6000 - 2.98 (2.32)
7200 - 4.30 (3.34)
8000 - 5.30 (4.12)
8200 - 5.57 (4.33)

Points of interest:
1. The same force appears to be exerted on the CP setup at ~8200rpm when the stock setup is running at ~7200rpm
2. No correction has been applied for either compression forces or torque forces

_________________
Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

yeh but can the eagle rods take the same force as the stock ones? I am not trying to rubbish them in anyway, it is just a question that we dont know the answer to YET!

_________________
JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

JP - good question. They are going to be tested at 8,500rpm very shortly, but not by myself!

Even though I have these rods I'm not sure whether they are the "wise" choice...time will tell.

_________________
Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

Going to know the answer soon enough as lots of people using or about to use chocolate rods in rebuilds.

Hopefully this all works out to be nothing more than scare mongering (fingers tightly crossed)

_________________
Loosey
Loosey@gt4dc.co.uk
Storm Blue JDM ST205
Super White JDM ST205
http://www.gtfours.co.uk

Some people are like a Slinky .. Not really good for anything, but they make you smile when you shove them down the stairs!

Yes I agree, Hopefully the re-design that I have heard of cured any possible problems in teh past.

Fingers crossed

_________________
JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

The conventional wisdom is that uprated rods are generally heavier than stock.

With the Eagles being approx 100g lighter (?) then unless they are using a much better material, then I can't see how they will match the strength of the heavier rods like the Arrow, Crower, HKS, TTE types.

I'm assuming of course that all other things are equal, surface finish, uniform metal density (v. important in rods) etc. etc.

My plan is to speak to people like Arrow and Farndon about 'finishing' my TTE rods as part of the balancing.

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

Update:

The Eagles have survived 8000 rpm and 500hp+ so far.

I will endeavour to get the owner of these rods to get a dyno plot together and claim his glory.

I drove the car at ~420hp so can verify that it's living and is "fairly" quick!

_________________
Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

Any info available on the balancing and preparation of the rods Kris?

I suspect the cases of broken rods (as opposed to bent rods) is due to poor or indequate prep for the eventual use of the car. Witness the recent article in Racecar Engineering which quoted an example of a K series engine with slightly out of balance counterweights producing an imbalance force of almost 1 tonne at 8,200rpm

The other interesting comment was that it is more important to match the centre of gravity for the rods than to match the weights. I wonder how many engine builders do that?

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

Good point. Just for completeness, the Eagles are ~218g lighter per rod vs the stock rods.

Personally I feel these are not as "strong" as some of the better known rods e.g. Pauter, Crower, TTE, Arrows etc.

I believe these are manufactured from a similar material, (4340), as these "better" rods. The increased strength of the above rods I would imagine would lie in them physically having more material than the Eagle i.e. thicker.

However, from the above info on "forces", I would've thought there would be a happy medium ground between longevity, performance and weight. I suppose there will be instances when a rod could be "too" heavy.

I think lightening is one way forward....but how light is too light?

_________________
Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

Hmm, was reading an article in a bike mag about the different designs of piston. Nice short skirts, additional bracing, materials and how long they are designed to last. I will review when I get home but basically it was how to extract 250bhp from 1000cc by getting mega revs. I think they rev superbike race engines similar to F1 engines. I also took a picture of the F1 Turbo era piston they had in teh shop @ brands. Had plenty of chants of "you sad B******" from teh peeps I was with lol.

_________________
JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

I run the CP / eagle rod combo at 8000 rpm and i have had no problems yet,that includes no piston slap like some other combinations.
Hutch

_________________
Please take your nails out of my dash..........501.1 Whp

CP's seem to get a good rap from most folks. I'm hanging fire on pistons until the Mahle items are available. They've been advertised in the US but they haven't been made yet .... grrrr!. If there's too much delay I'll go with the CP's.

Did you shot peen or polish the Eagle rods or just balance and fit them as they came?

There's a story circulating about Mk2 Eagle EVO (modified) rods but nobody seems to have any details. The Eagle design around the small end should actually be stronger than my TTE's relatively speaking.

TBH if they are balanced and prepped right they will probably be fine.

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

Shorts skirts I believe will be noisy and will help to wear the bores at an accelerated rate

The Eagles have already had a few processes done to them by the time you receive them

Without recapping on already covered material; I think any rod can fail under the right conditions. I suppose a possible conclusion to draw is how/why a particular rod failed given the circumstances they were operating under.

_________________
Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

You mean they say a prayer for them before they leave the factory

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

So does Kris have Halal or Kosha Rods?

_________________
JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R