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It's been awhile. Ended up putting a stock bottom end 5.3 lc9 with a btr stage 3 cam in the car. Been driving it around the last few years letting the holley do it's thing as far as tuning. Finally it's was time to get that dyno tune and get back the track in the upcoming weeks. Well 2nd pull on the dyno it sounds like it spun a rod bearing. Now have to pick who to get a built motor from or try a stock bottom end again?
Take that LC9 block, add a Summit forged rotator and let it eat.
Lots of guys running that combo really hard, @Prostock John is building one right now.
I wanted to find what the nosie was since it kinda sounded like a squeaking noise. So i pulled the heads off to see if it was a lifter or cam all looked good. Pulled the oil pan really didn't see anything. No metal or anything else in the bottom of the pan. So ended up pulling the motor and seen the cylinder 1 rod was bent and rubbing the crank. Ended up buying a few used stock long blocks what a nightmare that was with them all having something wrong with them. So I took 1 of the rods out and replaced it. Got it back together today sounds good and has good oil pressure. Not really sure what made the rod bend so I had the injectors cleaned and flowed didn't nothing crazy there so see what happens now will turn down the boost a little was at 17psi on the dyno.
Finally pulled out the aluminum 5.3 lc9 and sleeved and stroked it to a 427, tfs235, Holley Hi Ram, btr cam s491 turbo. Made 824 on pumpgas 17psi and 1139 on c16 30 psi
Maybe some extra power to be had with some better matched heads to the new cubic inch?
Really needs a better turbo to take adadvantage of the setup. The exhaust wheel and housing is to small has to much back pressure even when it was a 370.
Really needs a better turbo to take adadvantage of the setup. The exhaust wheel and housing is to small has to much back pressure even when it was a 370.
My TNT 88/96 has a 9 blade turbine wheel on it and while I do log back pressure I need one of those little canisters to smooth things out, it's currently just on a length of stainless tubing. At about 13 psi of boost its showing 20.8 psi of back pressure at 6800 rpm
I never heard of that company would like to see back to back compare data to make it worth trying. I think with my setup it just needs a completely different turbo to make a big enough difference to be worth it but I dont have the room with redoing front whole front end. Not something I want to get into at this point
I never heard of that company would like to see back to back compare data to make it worth trying. I think with my setup it just needs a completely different turbo to make a big enough difference to be worth it but I dont have the room with redoing front whole front end. Not something I want to get into at this point
Nearly 1,200whp is pretty fricken stout for a streetcar my friend.
I'd probably leave it alone for a bit and go get that 7.
FIS has some bigger turbines offered in their GTR line? Forced Inductions. GTR 102
Someone would definitely scoop up that current turbo.
I wanted to find what the nosie was since it kinda sounded like a squeaking noise. So i pulled the heads off to see if it was a lifter or cam all looked good. Pulled the oil pan really didn't see anything. No metal or anything else in the bottom of the pan. So ended up pulling the motor and seen the cylinder 1 rod was bent and rubbing the crank. Ended up buying a few used stock long blocks what a nightmare that was with them all having something wrong with them. So I took 1 of the rods out and replaced it. Got it back together today sounds good and has good oil pressure. Not really sure what made the rod bend so I had the injectors cleaned and flowed didn't nothing crazy there so see what happens now will turn down the boost a little was at 17psi on the dyno.
I know this was on your old setup but torque is what bends rods, not fuel injectors. Turn the boost down and/or reduce timing in the high load torque areas.
Originally Posted by stmz28
Finally pulled out the aluminum 5.3 lc9 and sleeved and stroked it to a 427, tfs235, Holley Hi Ram, btr cam s491 turbo. Made 824 on pumpgas 17psi and 1139 on c16 30 psi
What BTR cam is it? Could be too small for a 427 for sure, or that turbo is just plain DONE on that engine. That's a 200 rwhp drop from where the converter coupled to where you let out at 175 mph so I would want to correlate that with engine RPM to see where it was really happening.
I know this was on your old setup but torque is what bends rods, not fuel injectors. Turn the boost down and/or reduce timing in the high load torque areas.
What BTR cam is it? Could be too small for a 427 for sure, or that turbo is just plain DONE on that engine. That's a 200 rwhp drop from where the converter coupled to where you let out at 175 mph so I would want to correlate that with engine RPM to see where it was really happening.
Are you referring to the steady drop in power from 129mph out to 175mph?
If he had enough cam or turbo it should continue to carry out correct?
Forgive me if the questions are dumb, trying to learn this stuff lol.
I know this was on your old setup but torque is what bends rods, not fuel injectors. Turn the boost down and/or reduce timing in the high load torque areas.
What BTR cam is it? Could be too small for a 427 for sure, or that turbo is just plain DONE on that engine. That's a 200 rwhp drop from where the converter coupled to where you let out at 175 mph so I would want to correlate that with engine RPM to see where it was really happening.
Cam was made for this setup and even the btr said turbo had to small of exhaust side. More boost means more back pressure with rpm = less power. Can not fit any turbo that is bigger outside dimensions
Are you referring to the steady drop in power from 129mph out to 175mph?
If he had enough cam or turbo it should continue to carry out correct?
Forgive me if the questions are dumb, trying to learn this stuff lol.
Yes, there is a huge limitation somewhere and it's likely the turbo itself but without knowing cam specs that's also a variable. Here is an example of a 427 with a pair of relatively small sized 6870s at only 20 psi with a healthy sized cam through a powerglide. For reference 175 mph = 7700 rpms in this graph. It's hard to show a stalled auto plotted over RPM because the entire graph shrinks up, so most stalled auto dynos are plotted over wheel speed to show what the converter is doing so somebody needs to tell you what engine RPM is at what wheel speed for correlation.
Cam was made for this setup and even the btr said turbo had to small of exhaust side. More boost means more back pressure with rpm = less power. Can not fit any turbo that is bigger outside dimensions
Oh no doubt the turbo is a bit small for the cubic inches, but without knowing what engine RPM correlates to or what the cam specs are nobody can really make any suggestions. Just need more info to try to help...
Oh no doubt the turbo is a bit small for the cubic inches, but without knowing what engine RPM correlates to or what the cam specs are nobody can really make any suggestions. Just need more info to try to help...
So, if the OP is contemplating twins, sounds like twin 6870's like in your example might be the move?
So, if the OP is contemplating twins, sounds like twin 6870's like in your example might be the move?
It's a good quick spooling option, but even those are small depending on power goals and they certainly have a good amount of hot side backpressure. If the goal is 1200 rwhp they will work great as they have some headroom at that power level. At full tilt I see right around 1450 rwhp through the glide with these turbos and they are done at 26 psi.
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