Swapped Rod Bolts
Thread Starter
Staging Lane
Joined: Aug 2009
Posts: 53
Likes: 0
From: Edmonton Alberta , Canada
Swapped Rod Bolts Hey,
Recently swapped rod bolts to ARP 2000's, lubed torqued and released 3 times to 40 ft/lbs.
i started the engine and let it reach operating temp @ idle.
shut it off and let it cool down naturally.
in theory the bolts should be heat cycled and ready to see some revs ?
and i dont wanna hear about rod resizing !
Recently swapped rod bolts to ARP 2000's, lubed torqued and released 3 times to 40 ft/lbs.
i started the engine and let it reach operating temp @ idle.
shut it off and let it cool down naturally.
in theory the bolts should be heat cycled and ready to see some revs ?
and i dont wanna hear about rod resizing !
Thread Starter
Staging Lane
Joined: Aug 2009
Posts: 53
Likes: 0
From: Edmonton Alberta , Canada
kidding.
erm T-rex cam, LS7 lifters with .050 preload ( preformance shop has had nothing but luck with them when they actually measure the required pushrod, instead of just dropping a size in there) F.A.S.T 90 & TB, PRC stage 1.0 LS6 heads, patriot Dual Gold "extremes" ( know a guy with LS1 RX7 thats spun to 7400 with those springs) yella terras. dual roller timing chain.
dynoed last week @ 438 rwhp/400 rwtq spinning to 6350 RPM, it still hadn't peaked. im hoping to spin it to 6800 rpm or so. tuner cranked up injector duty to %120, but we didnt see a difference in the a/f ratio . He thinks my stock fuel pump is maxed out , racetronix is in the mail.
i dont understand how some people manage to lay down more power with cam only cars. im thinking the tuner is going conservative, and his dyno might be a little less friendly that some others
Thread Starter
Staging Lane
Joined: Aug 2009
Posts: 53
Likes: 0
From: Edmonton Alberta , Canada
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TECH Senior Member
Joined: Apr 2002
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From: So.Cal.
As was said above the injectors are STATIC OPEN when duty cycle is 100%.
If you try to drive duty cycle above 100% motor will run lean, and at load it will go kaboom.
You need your injectors to be just big enough so that they max duty cycle ever seen is 80-85%... this gives you a safety margin.
Which type is your FPR: un-referenced (constant pressure) or manifold-referenced (air hose from manifold)...?
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
Rule of thumb calculations... e.g. say you want 500 FWHP...
then:
at BSFC 0.45: peak IFR = 500*0.45 / 0.85 / 8 = 33.1 lb/hr
at BSFC 0.50: peak IFR = 500*0.50 / 0.85 / 8 = 36.8 lb/hr
Now, your 36 lb/hr @43.5 psi injectors will flow 36*sqrt(58/43.5) = 41.6 lb/hr @58 psi...
So you have enough injector... you should see at most ~85% duty cycle.
So the problem is your tuner is doing something wrong...!!!
Sorry for hijacking your thread.
</hijack>
then:
at BSFC 0.45: peak IFR = 500*0.45 / 0.85 / 8 = 33.1 lb/hr
at BSFC 0.50: peak IFR = 500*0.50 / 0.85 / 8 = 36.8 lb/hr
Now, your 36 lb/hr @43.5 psi injectors will flow 36*sqrt(58/43.5) = 41.6 lb/hr @58 psi...
So you have enough injector... you should see at most ~85% duty cycle.
So the problem is your tuner is doing something wrong...!!!
Sorry for hijacking your thread.
</hijack>
Thread Starter
Staging Lane
Joined: Aug 2009
Posts: 53
Likes: 0
From: Edmonton Alberta , Canada
next thread i write , i will never put the words "rod" and "bolt" in the same post.
Anyways I ordered the Racetronix pump and wire kit.
joecar, Thanks for showing how to calc. the injector size needed. never really thought there was much more than looking @ injector duty cycle, and going up in size from there if you didnt have enough.
from the graph i saw, the car was running lean down low, then it fattened up up top to close to 12.7 ( which i thought was weird ). the tuner has built/tuned quite a few LSX engines, and ran a TT 6.0 for a whole season plus some 70,000 kms. Although there is one other option close to me , they have a mustang dyno, getting in is hard though.
Anyways I ordered the Racetronix pump and wire kit.
joecar, Thanks for showing how to calc. the injector size needed. never really thought there was much more than looking @ injector duty cycle, and going up in size from there if you didnt have enough.
from the graph i saw, the car was running lean down low, then it fattened up up top to close to 12.7 ( which i thought was weird ). the tuner has built/tuned quite a few LSX engines, and ran a TT 6.0 for a whole season plus some 70,000 kms. Although there is one other option close to me , they have a mustang dyno, getting in is hard though.
Because instead of having seperate forgings (rod cap and rod beam) which then get machined and made round with a flat mating surface, they take a one piece casting, machine the hole perfectly round, and then do the equivalent of putting it on the edge of a table and breaking the cap off.
This does have a perfect fit as the jagged edges mate perfectly, but can't be resized in the conventional manner.
When resizing out of round or egg shaped rods, one has to cut the flat surface to make the hole a bit smaller and then rebore the hole on the big end to spec.
You can't machine flat the granular cracked rod halves and refit.
This does have a perfect fit as the jagged edges mate perfectly, but can't be resized in the conventional manner.
When resizing out of round or egg shaped rods, one has to cut the flat surface to make the hole a bit smaller and then rebore the hole on the big end to spec.
You can't machine flat the granular cracked rod halves and refit.
Last edited by bigboykilroy; May 5, 2010 at 08:31 AM.
People usually aren't willing to go through all of that trouble, so they skip that and swap them in anyways. I'll keep my comments about that to myself, since that is not what this thread is about.
Hey,
Recently swapped rod bolts to ARP 2000's, lubed torqued and released 3 times to 40 ft/lbs.
i started the engine and let it reach operating temp @ idle.
shut it off and let it cool down naturally.
in theory the bolts should be heat cycled and ready to see some revs ?
and i dont wanna hear about rod resizing !
Recently swapped rod bolts to ARP 2000's, lubed torqued and released 3 times to 40 ft/lbs.
i started the engine and let it reach operating temp @ idle.
shut it off and let it cool down naturally.
in theory the bolts should be heat cycled and ready to see some revs ?
and i dont wanna hear about rod resizing !
Bingo. Instead of machining the parting surfaces, like the old school stuff, you just hone the big end larger. There are A LOT of people who still think that resizing these rods is impossible or much more difficult (including certain magazine editors), when in fact it is easier since you skip an entire process. Clevite, ACL, and King all make bearings in a .002" oversize for this reason. On the downside, these bearings are meant for a full rebuild since the bearings are thicker for a crank ground .010" under.
People usually aren't willing to go through all of that trouble, so they skip that and swap them in anyways. I'll keep my comments about that to myself, since that is not what this thread is about.
People usually aren't willing to go through all of that trouble, so they skip that and swap them in anyways. I'll keep my comments about that to myself, since that is not what this thread is about.
again, i love the people who dont know what they are talking about, but flaunt it anyways like they do. no reason a cracked rod cant be resized.
Because instead of having seperate forgings (rod cap and rod beam) which then get machined and made round with a flat mating surface, they take a one piece casting, machine the hole perfectly round, and then do the equivalent of putting it on the edge of a table and breaking the cap off.
This does have a perfect fit as the jagged edges mate perfectly, but can't be resized in the conventional manner.
When resizing out of round or egg shaped rods, one has to cut the flat surface to make the hole a bit smaller and then rebore the hole on the big end to spec.
You can't machine flat the granular cracked rod halves and refit.
This does have a perfect fit as the jagged edges mate perfectly, but can't be resized in the conventional manner.
When resizing out of round or egg shaped rods, one has to cut the flat surface to make the hole a bit smaller and then rebore the hole on the big end to spec.
You can't machine flat the granular cracked rod halves and refit.