The black bitch.

I believe im going to have rod problems the motor is making 650 + 330 shot = bent rod ?? Does anyone have big motors with ti rods ,I haven't heard of bent rods being a problem ?

40YRW8

The last I remember hearing from Jason at Katech was that they had never seen a broken titanium rod. Most of the stress comes from RPM and not horsepower/torque. I wish all the guys that replaced their titanium rods with forged steel "Just to be safe" had sent their weak old titanium rods to me for disposal.
Gary

American Heritage

I don't think most people think the stock ti rods are weak. I think alot of people want to replace them based off the packages that some of the larger company's offer. Most these company's start shying away from the stock ti rods in the 700-800hp range. Nothing like a good forged rod but the stock Ti rods are plenty strong for 95% of the Z's population.

OP what are your power goals with this engine? how do you plan on getting there (n/a, FI)? just notice you said a shot. Well if it makes you feel any better we have run a 250 shot on the stock rods before with no issues to speak of.

The black bitch.

I think I agree I've looked ad I've never seen a issue with the rods and I've also talked to Jason (I have k501 cam) I think a putting a huge shot of nitrous is really going to test them,I'll know soon.

BOO666

From what I've been told Jared uses stock rods and Mahle extreme duty pistons . Keeps rotating mass same as factory

The black bitch.

I've seen that run about 50 times I think I have more power but he's tough out of hole ,I'm really hoping for 8s also but low 9a will work. Just waiting for cool weather here in San Antonio to hit the track

BOO666

If you think you have more power it's just a matter of seat time , clutch and weight savings . It takes a while to iron it all out . You know that already lol . Sounds like its gonna be nasty

Michael_D

I don't think anyone really knows what the Ti rods are good for.... Seems as if the engine builders just move to a steel rod at about 750 crank HP mark, or 8000 rpm. I had a conversation with a GM racing power train manager who has a great deal of experience with the LS7. Asked him flat out what power levels the rods are good for. He told he couldn't give me a definitive answer. Katech probably has a pretty good idea. They are well known for improving on the OE rod. I'd start there and find out what they have to say before going over the 750 mark.

Chance42

I was at 760 rwhp on stock rotating assembly. The crank and rods held up fine. The pistons on the other hand...

BOO666

From all I've seen over the years at the shop . Use the stock rods with different rod bolts and change the pistons to the light weight mahal extreme duty style . Your good unless you want big power . We have a Camaro at the shop that takes a beating more than often and no problems with this set up on a ls7 . I've never seen one come through with a broken rod . Always rings or valve train related .

40YRW8

My personal opinion is that if you have a heads/cam car and you are going to dump a 250 shot, you have a lot more to worry about before the rods become a concern. It may sound illogical but the most destructive stress that a rod sees is at TDC on the overlap and the problem is tension, not compression or bending stresses. I personally think that the stock rod bolts are pretty good but better bolts are always a source of cheap insurance. Running a lighter piston takes a lot of stress off the rod bolts at the same RPM and very few here actually raise their rev limit. However, I wouldn't raise the rev limit by 500 or more without changing the stock bolts. The rods themselves are one of the best things about our motors. GM didn't spend the money on them just because they were "Cool".
Gary

Michael_D

Great point. I think it was Vizard who said "It's the stops that kill parts, not the starts". I have a calculator that I use to model stress on recipicating components for this very reason.

The black bitch.

I have forged pistons, I would be worried at even 150 shot without forged pistons and I have the k501 cam and erl superdeck block I'm not going over 7000 rpm ,so I think I'm safe . Thanks for all the input

BOO666

My first serious n20 motor was a small block ford . 3.900 stroke 4.130 bore . 9.5 deck block with grp 6.125 rods and venolia pistons . Bennett racing Yates sc1 heads and intake . Pro systems dominator and built by buck racing engines .. They are a pro mod builder . It had 3 kits . Two 200 foggers and a custom spray bar . Whew . It was hell on wheels literally ! N20 is a lot of fun . I also remember replacing pistons in the pits . A small plate system is very forgiving and easy to tune

Mark2009

Good point on the TDC issue. IIRC the LS7 uses eccentric rod bearings for this very reason ('pinch' along the parting line at TDC).

Or in other words, what goes up must come down

Pistons are essentially cast and not expected to survive much above stock power levels. That being said, I certainly wouldn't want anything heavier in replacement.

Bad_AX

I would favor keeping the stock rods with a bushing and bolt upgrade and going with forged pistons. JE has a new line of LS slipper skirt pistons that will shave off about 40 grams of weight versus the factory cast pistons. They have put a lot of engineering into the LS series pistons to achieve good street manners too.

Michael_D

JE is my default piston. For mild street builds, I tend to gravitate towards their SRP line. You can run a tighter bore clearance with the SRP, but they are still hell for stout. They do not have one for 4.125 bore though, unfortunately. The slipper skirt would be a good one for mild boost. -22 dish. I’m also a Speed Pro/Plasma Moly ring fan.

briancb1

Along with a set of double hump heads with 2.02" valves, HEI ignition and a Torker II intake from a PWI paper catalog?... Just messing with you bro!



OP: Unless you're planning on your piston speed operating at 4000fpm+ all the time, I would worry more about your tune, pistons and rings than your rods.... That and the quality of electrical work hooking everything up

Keep us posted.

The black bitch.

Hey I had all that but a victor jr on a 70 vette , briancb1 !! And it was damn fast 13s (for the 80s) I have great mechanic ,jack at lethal performance adding a stand alone fuel sys. For the nitrous and she's done !

ProEFI

Will we're gonna use them on my friend car we'll go with 16psi on his D1 and spray 100 we're not sure it will handle it or not but we're planning to go with dragon slayer and coated pistons.