Can you spin an LS1 to 7800 with the right valvetrain in a 346? What would you need?
Phil

 

solid roller would get you there.

 

I think that's asking alot.

Titanium everything and a few prayers.

The LS7 set a precedence with 7100 RPM.

Getting anymore from a 346 at 7800 RPM would probably require boost.

 

7800 RPM and Hydraulic Roller is doable. I'd go with Solid Roller for the safety factor, however several in the Ford Camp are taking Hydraulic Rollers straight to 8000 RPMS.

Are you looking for valvetrain reccomendations or something else?

 

On a stock bottom end or on a forged one. If you have a fored bottom end you might make it there. I would bet you would have 15k in a motor that could do 7800

 

Definately a solid roller would hold up in that range. Talk to Alan Futral at FMS. His car regularly sees 7500+rpms and is running VERY strong. I see the lifter failure being you're biggest limiting factor. That is, assuming your valvesprings/bottom end are up to it.

 

Youll also need ***** that clang togather when you walk.

 

Why is it that everyone speaks of titanium everything when they talk about high rpm engines? I mean honestly, I've never figured it out, cars have been going 8k+ for longer than titanium has been used as a piece in *some* valvetrains.

Someone give me some info please, or next I'll be reading about triangular pushrods, and so forth.

 

I have a custom 3 piece connecting rod at my house from a motor that was spinning to 7000rpm.It broke because the rod bearing went and shot through the pan.So I would say you need the lower end built for high rpm,346 rods/pistons are pretty heavy.
We have out shop Mustang revving to 8500rpm with stock lifter's but we compensate it with 120psi of oil pressure to keep the lifters pumped up.

 

I will be trying this with my upcomming 408. Many members spin that high, it is not as hard as you think. No stocker rockers and xe-r lobed hydraulics though. Solid for safety sake. You may be able to obtain that kind of rpm with hydraulic but for how long. Plus you'd have to use such a soft lobe to do it that you'd give up a substantial amount of power just to retain hydraulic lifters.

 

7800 is not asking much. I spin my 408 over 8000 on a regular basis. It will see close to 9000 this fall. Hydraulic will do it, but a solid roller would be best.

 

Friend of mine out here spins his stock bottom end, stock lifters, dual springs, stock rockers, hardened pushrod engine to 7600 rpms and hasn't had a problem yet. I used to take mine to 7500 however just because it can be done doesn't mean it will last long.

-Sly

 

Titanium is lighter. You want to reduce reciprocating mass as much as possible.

As RPM inceases, so does the effective mass of the object.

Reducing even a couple of grams on the entire assembly is a huge deal at high RPM.

The "everything" reference was to stress the point, obviously, it wasnt to
be taken literally.

Besides that, do you think getting 600-800 RPM more peak from a naturally
aspirated LS1/6 engine will be easy?

 

 

Are you using the ls1 PCM?

 

Yes, for now. Soon to be using TEC3. It's tuned in open loop speed density.

 

I thought you would be limited to 7800 rpm with the ls1 pcm. These are the highest cells that exist in the ls1 edit file I have looked at if memory serves correct. How did you carry the extra 200 rpm or is it just so close that it is a non issue? Thanks.

 

I've seen 8000rpm cells in HPTuners if I remember correctly.

 

Stock computer goes to 8k rpm. Are you guys running sheet metal or carb style intakes reving that high?

 

My HPTuners bin goes to 8000rpm, which I was under the impession was the limit of the OBDII pcm's max limit.