Building for turbo?
11-04-2015, 11:43 PM
#1
Building for turbo? Any ideas what people recommend for a 700rwhp + turbo build strength wise?
I have my topend built fully already. I am getting rod bolts, head studs, best gaskets possible, and new bearings.
Crank I was keeping stock. I am up in the air about rods and pistons? What power can the stock rods and pistons handle? Or, if people usually change them for turbo even with rod bolts, what is a decent rod & piston set to buy that isn't something like $1500? Doing a 700rwhp build here, so not looking for pistons and rods meant for a 1200rwhp build lol. However if I can get decent pistons for around $500 mark or so, I would def. consider it.
I have my topend built fully already. I am getting rod bolts, head studs, best gaskets possible, and new bearings.
Crank I was keeping stock. I am up in the air about rods and pistons? What power can the stock rods and pistons handle? Or, if people usually change them for turbo even with rod bolts, what is a decent rod & piston set to buy that isn't something like $1500? Doing a 700rwhp build here, so not looking for pistons and rods meant for a 1200rwhp build lol. However if I can get decent pistons for around $500 mark or so, I would def. consider it.
11-24-2015, 07:07 AM
#9
Restricted User
11-24-2015, 10:06 AM
#12
I don't plan on reving past 6800 like I do now with or without boost. You would suggest leaving everything go as is for a turbo kit instead of doing rod bolts? I have heard the rod bolts are the weak part, not the rods themselves as much.
11-24-2015, 11:23 AM
#15
Well that's the thing, I plan to keep it the same 65-6800rpms anyways (Probably 6500). The thing I'm not sure on is while everything is apart spend some money and do rod bolts and new bearings or leave it. If leaving it the way it is at 108k miles will handle what im doing then I would. I'm just worried because of mileage that maybe while everything is out to do the rod bolts and new bearings for some added relief. Can more chime in who have a turbo or have experience with 600rwhp+ boost builds?
11-24-2015, 11:47 AM
#17
Restricted User
Want me to show you lots of pics of broken and mangled rods with the bolts still in place?
Rod bolts see the most stress at the top of the exhaust stroke. The piston forces the exhaust out, and then is stopped and yanked back in the opposite direction with no force coming from the top. Heavy pistons/rods and high RPM put stress on the bolts. Turbo engines have high exhaust pressure and positive intake pressure, reducing the stress on the bolts between the exhaust and intake stroke at TDC.
When you have ignition and the piston is being forced down creating torque, the rod bolts see almost zero stress. Even the cap is being pushed against the journal by the downward moving crank, so technically with both halves of the rod being forced into the crank, the bolts will see a couple ten-thousands of extra clearance at high cylinder pressures and will actually see reduced stress.
But if you want to buy bolts, have the rods line-honed to ensure they are round, and then order the special clearance bearings from Clevite, so you feel better, you can do that.
99% of the guys here that make 4 digit power and torque numbers bend gen 4 rods long before they ever have issues with the bolts.
Rod bolts see the most stress at the top of the exhaust stroke. The piston forces the exhaust out, and then is stopped and yanked back in the opposite direction with no force coming from the top. Heavy pistons/rods and high RPM put stress on the bolts. Turbo engines have high exhaust pressure and positive intake pressure, reducing the stress on the bolts between the exhaust and intake stroke at TDC.
When you have ignition and the piston is being forced down creating torque, the rod bolts see almost zero stress. Even the cap is being pushed against the journal by the downward moving crank, so technically with both halves of the rod being forced into the crank, the bolts will see a couple ten-thousands of extra clearance at high cylinder pressures and will actually see reduced stress.
But if you want to buy bolts, have the rods line-honed to ensure they are round, and then order the special clearance bearings from Clevite, so you feel better, you can do that.
99% of the guys here that make 4 digit power and torque numbers bend gen 4 rods long before they ever have issues with the bolts.
11-24-2015, 11:59 PM
#18
If that's the case I won't even bother. I kinda wanted to put new bearings on just because of the mileage, would you say change them just while the motor is out or leave it be? I have my topend built, ported ls6 oil pump already, and car has been run with amsoil race oil since camswap years ago so engine is definitely maintained.
