Hey HT, I have a technical question about lightweight crankshafts in a turbo application.

I talked with Sean today ERL Performance and as we were discussing my upcoming engine build on a B18A and we got on the topic of crankshafts.

I know that the stock crank can handle almost anything that is thrown at it. With that being said:

Sean told me that using a light weight "Knife edged crankshaft from Eagle" wasnt a good idea in a High HP turbo motor being 400-550 HP.

this dis-comforted me, seeing in how i already bought the Stock stroke Crank from eagle (1,100$)

Sean said that the Eagle crank will flex to much under load.

So i think ill tell you guys how i would like my engine to perform:

Ive decided that ERL will assemble my shortblock Im having everything done to the block that can possiably be don, Assembly, berrings sleved, JE pistons etc.

But i really want my engine to rev lightning quick.. andi know a lighter crank will help in that area by reducing rotating mass.

Based on those facts from a Professional builder......

I just want to know what some of the engine builder on HT had to say about it. I would really like your opinions, tech info, and experience to show the pros and cons of the crank.




Thank's guys

Nick

 

It's good you are looking for a second opinion. Do you know the big players here on Honda-Tech? Just remember you'll get about 90% crap and 10% good stuff. Wait for the intelligent guys to chime in. But on a side note, Sean gets a in my book....he knows his ****.

 

I wouldnt use a light weight crank in a turbo motor but thats just me..I would rather have a heavier crank so it can handle more abuse..thats why I went to a type r crank over a gsr (3 lbs heavier)..

 

WOW i appreciate the reply's ----

and as for the big players on HT... maybe not so much, ive been reading on ht for a couple of months now and know "read" about some of the tuners. I know there are some wicked cars on here. that's why i was looking for a couple of opinions, or experience.

Im not doubting Sean at ERL one BIT... he is a professional... and does this day in and day out. I realy like the way he told me that it wasnt a good idea, he made the explination short and sweet.

If it all turns out i may or may not have a crank for sale...

Keep the replys coming.

thank's

Nick

 

yeah i "thought " that the Eagle Crank being made out of 4340 same as there rods. would be equivelent or greater in durability/strength.

But hey I dont have anything to base that asumption off of. Its not like i have Built 300 B series motors. lol

thanks again



Nick

 

As for the "big guys" on here you'll figure out quickly just by sticking in this forum who frequents/posts in it alot. Also the typical names that people will say are: Mase, Earl, Tony1, Jeff Evans (BoostedHybrid...I think).

 

Thanks

 

im with 99Hybrid_Hatch on this one. put the toughest parts you can in a turbo motor... boost is like crack, you get a little and want it all. you say 400-500hp right now, but who's to say that down the road you might stick a 42r on it and go for 800.

if you want super fast revs then get that with a lightweight clutch assembly. we did a 89mm stroker on my friends b16 with a tilton twin disk, that thing reved like a bike. shelf wiseco pistons are pretty light and rod weight dosnt make "that" much difference... remember the closer it is to the center of rotation the less the weight matters.

 

that makes alot of sense.... and yes i know boost = crack. my 92 mr2 turbo was a blast- then i turned up the boost 4 pounds.. then it was fun- well you get the idea, i sold that car to a riend of mine still runs great.

But 800 HP?.. no matter what im not going that high, this is a daily driver, and engine's dont last that long at 6 times there original power, even if it is built. No i've decided that 400-550 is my max.

But thank you for your input its greatly appreciated.

Has anyone usedthe Eagle crank in a turbo motor before? how did that turn out?

anyone else?

 

bump


Mase, Tony1 .... anyone?

 

The proper sized turbo on your build will rev so fast that a lightened crank is useless. Strength and stability is more important. Stock cranks seem to be good for close to 1000hp anyway. A $1100 Eagle crank made in Taiwan is probably a step down from oem. If you like and trust the engine builder you chose, then listen to what he says and don't try to second guess him.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Importordomestic &raquo;</TD></TR><TR><TD CLASS="quote">bump


Mase, Tony1 .... anyone? </TD></TR></TABLE>


people ask me all the time about motor builds.

while im not an engine builder by any means, ive built several setups that have done extremely well.

I like to follow the old saying "KISS: Keep It Simple Stupid"

I like oem parts. (besides pistons, rods, sleeves.)

i personally havent seen a honda crank fail first hand. im sure they will on 1000 + WHP applications.

so the way i look at it, if you're not going to make that kind of power, why change it out? they are known to virtually never fail.

i realize you already bought it, but im sure you can turn around and sell it.

like jdogg said, if u want a fast reving setup, go with a very light flywheel. tilton makes great products, and they arent that hard to get the feel for.

otherwise if you're talking about a fast reving motor while in motion. pick a great turbo setup with a broad power band.... these huge turbos are laggy as hell, and while they make insane power up top, the bottom end and mid range just isnt there...

 

I cant believe you spent that much money on a crank!

 

Just and Idea... I was talking to one of my prof's who builds engines (sleds, cars ect.), I asked him about knife edging my crank and if it would be reliable in a turbo'd car. He told me that when they knife edge the cranks in their race cars, that it should be knifed upwards.. \_ If that makes any sense.. also he mentioned that when they decreased the area (and mass) of the crank that they would put in heavy metals into the crank to help with the balancing process and to maintain the desired mass, but reduce the radius of gyration of the crank itself.. im not sure if this helps at all, but hopefully things work out.

good luck,

mitch

 

all motor car yes...turbo car no......simply put....but glad your doing your home work.


harv

 

Have u guy compare the OEM crank to the eagle lightweight crank?I have a change to compare the two and i will choose the eagle any day.We are buildin a engine with the eagle crank looking to put 700whp+ will see how it hold up

 

I went with an ITR crank on my setup and and ACT flywheel. The ITR crank is heavier than a gsr crank as said earlier and combined with a light weight flywheel I am ahead only a few pounds. I am also no engine builder, but I agree all OEM parts!!! If you want to drop even more weight get your OEM crank pully turned down or by a CTR (might be wrong) and that will save you a few more lbs. Besides when the tires break loose it will rev faster than you want anyway....

 

Well it seems that i have done something stupid..... lol i bought something that turns out isnt exactly what i had intended.

The best lessons learned are the hard ones.

Mase, Erl, and all the other guys that have given such good information on this thread. I thank you alot.

I do trust Sean at ERL, he has more experience than me and so many people do. I am just trying to learn as much as much as i can.

with that crank in ther it will probably blow from reving tooo quick... but hey im the ameture.

thank you guys for theinput once again. I believe im going in the right directin now.

anyone want to buy a crankshaft? for a NA setup....lol CHEAP 600$ OBO im loosing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote"> A $1100 Eagle crank made in Taiwan is probably a step down from oem.</TD></TR></TABLE>

Gimme a Break...Eagle Cranks are in Tons of V8, Turbo Setups making 1500hp+.

I know of plenty of guys that run Eagle Cranks in Blower\Turbo Big Power Applications...The only thing they aren't meant for is Big Nitrous Combo's where the peak cylinder pressures are insane...Chromoly is Chromoly, it all comes from China anyways...the only difference would be quality control in the machining process. If you have a crank properly checked by your machine shop (fluxed, mic'd and balanced)...You should never have a problem that you wouldnt have with stock. Anyone who has seen an Eagle Lightweight Crank would know that the weight is taken off in the counterweights.

That being said, I would sell that **** and use the money elsewhere...$1100 is some loot. If noone will buy it, run that ****...

 

LOL, I hope your are checking those cranks for more than that. Every crank comes off the boat bent because they are not supported properly. They must be straightened. If you want a good laugh, have the crank indexed and see how many degrees they vary. Maybe you think Chinese machine work is great but I don't. Let's not even go into their heat treating or lack of it. For price or quality, you can't beat OEM.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mase &raquo;</TD></TR><TR><TD CLASS="quote">p
I like oem parts. (besides pistons, rods, sleeves.)

</TD></TR></TABLE>

so basically you like the honda casting of the block?

nOice

 

Have yu seen an Eagle Crank fail ina Honda?

A messed up crank is a messed up crank...there are plenty of OEM Ones that are garbage and shouldnt be in a race motor. If yu don't check you parts, you are going to run into problems whether it be OEM or Otherwise. I would hate to see this guy put a perfectly good crank in the corner and put some junkyard LS Crank in his car just because you guys scared him.

 

That was my reasoning behind buying the crankshaft anyway, and the crank is lightned only on the counterweights. also precision balanced to 10,000 rpm from the factory. I know eagle makes good stuff. IF they didnt they wouldnt be in business.

But more and more im told that this crankshaft will flex and or be 2 light. its only 10 pounds lighter than stock. i thought it would give me an edge on rpm gain.

The motor will make TQ either way you look at it, that is one of the things that comes from a 84mm 89mmstroke b18 witha turbo. but it seems that the eagle crank is not durable enough to stand that kind of power rating.

I dont know maybe i am walking on thin ICE.... who knows it might a combination that just makes some wicked power.

im using one of the longest geard transmissions on my build, (daily driven) the A1 with a lsd conversion.

I thought it would have been better to have the rpm's gain quicker on a long geared transmission.

still selling the carnk and using the moeny to pay sean to work on the block still seems a better option at this point.

 

If you are torn between the two go with OEM. At least it is proven!!!! Your building a daily driver/street car from the sounds of it, so why risk it. Follow your gut and use the money on something that will add reliability.

 

your point is well proven. i hate the fact i have this pretty part i cant do anyting with.

its like im trying to put ice back together with a heat-gun.

hopeful im able to sell the crank before i ship my block to ERL, (3 weeks).

ill just put it up for sale on HT this friday.i only have one vouch tho.

Thanks guys.