Yellow Bullet Forums banner

1 - 20 of 20 Posts

·
Registered
Joined
·
51 Posts
Discussion Starter #1
What's the deal with using aluminum rods and being told you should use a brake with clean neutral? Getting ready to build a trans (T-400). Do I need an aluminum drum and a trans brake with clean neutral? Why do some say you should with aluminum rods? Approx. 725hp/ 650 ft. lbs. naturally aspirated. 3400lb car (for now). Plans on making it lighter and adding more power later. Eventual goal is deep in the 9's so I want to plan for future and build the trans I need for the future, now.
 

·
Registered
Joined
·
301 Posts
I run Aluminium Rods and a TH 400. The motor braking makes me a little nervous. My trap speed in SST is mid 150's. I am also 3550 lbs. Since all the tracks we run typically have a long shut down. I try to gently feather the throttle through the shutdown. The aluminium in the rods are better than it was years ago but I still try to take it easy on them. That doesn't mean I wont whomp on it at the stripe.:cool:
 

·
Registered
Joined
·
9,206 Posts
Why even bother with aluminum rods at your power level and rpm??
Not worth it...
I've got a customer who runs an ultra street 582 BBC that makes about 1700 on the spray running Carrillo steel rods....
That would be an excellent candidate for aluminum... But customer wanted steel....
It has been perfectly fine and runs to 8300 rpm every pass....
It is 1/8 mile but
It goes 4.59 @ 155
Weighing 3230lbs
 

·
Registered
Joined
·
51 Posts
Discussion Starter #4
Why even bother with aluminum rods at your power level and rpm??
Not worth it...
I've got a customer who runs an ultra street 582 BBC that makes about 1700 on the spray running Carrillo steel rods....
That would be an excellent candidate for aluminum... But customer wanted steel....
It has been perfectly fine and runs to 8300 rpm every pass....
It is 1/8 mile but
It goes 4.59 @ 155
Weighing 3230lbs
I've made a 1000 n/a before w/ steel rods so yes, you're right. Long story, but the short answer is that it's what I have and I'm going to use it. And this is a new build. I want to get used to the car since I've been out of it for about 6 years now, then I'm going to add better heads, bigger cam , etc. Shooting for 900-ish eventually.
 

·
KEVIN CAPS LOCK
Joined
·
78,153 Posts
ID SAY EVERYTHING SHOULDNT HAVE TO DEAL WITH THE AFTER AFFECTS OF ENGINE BRAKING DOWN FROM 150 PLUS... JUST MORE VARIABLES THAT COULD GO WRONG...JMO
 

·
Registered
Joined
·
9,206 Posts
I've made a 1000 n/a before w/ steel rods so yes, you're right. Long story, but the short answer is that it's what I have and I'm going to use it. And this is a new build. I want to get used to the car since I've been out of it for about 6 years now, then I'm going to add better heads, bigger cam , etc. Shooting for 900-ish eventually.
900 HP, still not needed, why if a new build did you go with Aluminum....
Cause it's cool or ?
 

·
Registered
Joined
·
51 Posts
Discussion Starter #7
900 HP, still not needed, why if a new build did you go with Aluminum....
Cause it's cool or ?
As I stated, it's what I had. Bought a lump sum of parts and these were brand new Bill Miller rods, with a forged crank and Ross pistons, and balanced. So why not use them. There were a ton of other parts also, but nothing ready to go like these were. Why spend more money to get steel rods and re-balance? Maybe I'll do that a couple hundred runs from now.
 

·
Registered
Joined
·
26,473 Posts
All I know is Bill Miller builds some of the finest, strongest aluminum rods in the world. I like aluminum rods, because they absorb most of the shock. But, that’s just me. That being said, I don’t use the engine to slow down the car.
 

·
Registered
Joined
·
2,291 Posts
OP my thoughts are build the transmission with the clean neutral since you are going to use the aluminum rods. As said above those are quality rods however less abuse the better.
SST469C fortunate to be able to race at tracks with a long shut down which is helpful if you don’t have a trans with clean neutral.
Good luck and I hope you get out there soon brother!

Steve
 

·
Registered
Joined
·
67,566 Posts
As I stated, it's what I had. Bought a lump sum of parts and these were brand new Bill Miller rods, with a forged crank and Ross pistons, and balanced. So why not use them. There were a ton of other parts also, but nothing ready to go like these were. Why spend more money to get steel rods and re-balance? Maybe I'll do that a couple hundred runs from now.
Miller's rods are some of the best alum rods out there. Call BME and ask them.
 

·
Q(t)=ṁCpΔT
Joined
·
26,314 Posts
News to me. Back when I raced, ran low 8's at 3400lbs. A neutral after 3rd wasnt available for torqueflites. So, after the strip it was in 3rd. Would get 230 runs out of a set of GRP's.
 

·
Registered
Joined
·
16,195 Posts
If its a fresh build, why not sell the BMR rods and put the right rod for you trans in it? Your saying its what you have, I get it, but if you're going to spend more money building a trans to accommodate the rods, whats the point?
 

·
Registered
Joined
·
3,886 Posts
If its a fresh build, why not sell the BMR rods and put the right rod for you trans in it? Your saying its what you have, I get it, but if you're going to spend more money building a trans to accommodate the rods, whats the point?

If you're building a trans around the rods you're going to use in your engine you're bassackwards and doing it wrong to begin with....
 

·
Registered
Joined
·
3,494 Posts
You can have your TH400 built so that it doesn't do "engine braking".. That's the way mine is..

It's not like a clean neutral, where you can shut the engine off when you cross the finish line.. But when I cross the line at 7000+ and let off the gas, my rpms fall back to about 4000 and drift down from there.. With no engine braking..

I don't have an in-car quartermile run (where you can see my tach) but the 1/8th mile below will give you an idea what I'm talking about.. BTW.. I run GRP rods myself..

 

·
I kill parts
Joined
·
9,957 Posts
You can have your TH400 built so that it doesn't do "engine braking".. That's the way mine is..

It's not like a clean neutral, where you can shut the engine off when you cross the finish line.. But when I cross the line at 7000+ and let off the gas, my rpms fall back to about 4000 and drift down from there.. With no engine braking..

I don't have an in-car quartermile run (where you can see my tach) but the 1/8th mile below will give you an idea what I'm talking about.. BTW.. I run GRP rods myself..
Even with a clean neutral, if you shut the engine off the pump is stopping along with it which means the drums will dump and can thusly allow the direct drum to over-speed.
 

·
Registered
Joined
·
1,394 Posts
it has very little to do with the rod and decel. it has more to do with oil pressure timing of the oil hole, and where the load is on the bearing in decel vs pressure timing.
the load is on the lower shell during decel, but the crank is timied to give the bearing pressure right before tdc on the upper (look at the groove in hte main bearing and how it feeds)
so loading the lower shell with little to no oil pressure is what causes issues IMO
we actually blew up a couple of 500"s because the clutch hung on the engine and the motor had to decel the car.
within 2 runs, it blew up.
Finally convinced them to pull the motor the next time it hung rather than run it and several lower shells had distress.
Sometimes its not possible to neutral the trans, i get that. ALL of my customers with a glide i make them neutral the engine
 

·
Registered
Joined
·
26,473 Posts
it has very little to do with the rod and decel. it has more to do with oil pressure timing of the oil hole, and where the load is on the bearing in decel vs pressure timing.
the load is on the lower shell during decel, but the crank is timied to give the bearing pressure right before tdc on the upper (look at the groove in hte main bearing and how it feeds)
so loading the lower shell with little to no oil pressure is what causes issues IMO
we actually blew up a couple of 500"s because the clutch hung on the engine and the motor had to decel the car.
within 2 runs, it blew up.
Finally convinced them to pull the motor the next time it hung rather than run it and several lower shells had distress.
Sometimes its not possible to neutral the trans, i get that. ALL of my customers with a glide i make them neutral the engine
Great explanation.
 

·
Registered
Joined
·
301 Posts
What weight oil and oil pressure? Also RPM?
it has very little to do with the rod and decel. it has more to do with oil pressure timing of the oil hole, and where the load is on the bearing in decel vs pressure timing.
the load is on the lower shell during decel, but the crank is timied to give the bearing pressure right before tdc on the upper (look at the groove in hte main bearing and how it feeds)
so loading the lower shell with little to no oil pressure is what causes issues IMO
we actually blew up a couple of 500"s because the clutch hung on the engine and the motor had to decel the car.
within 2 runs, it blew up.
Finally convinced them to pull the motor the next time it hung rather than run it and several lower shells had distress.
Sometimes its not possible to neutral the trans, i get that. ALL of my customers with a glide i make them neutral the engine
 
1 - 20 of 20 Posts
Top