7000 rpm?

[Motorboy8769]

I don’t know exactly what a Bare cradle weighs. Im hoping for 100lbs off maybe more I will have smaller and lighter brakes on the back plus a couple lbs lighter rims. Plus to do he 4 link I have to use a fuel call so I may Lois a little ditching the factory tank.
Once I get a cage in the car I’m going to cut all the un needed double wall steel that they cut off of the copo. They are 2900 dry I believe.

Here is a pic of the scale

[BEaSSy]

You have me thinking pretty hard about a 4link now... I'm sure that we'll eventually have to go the route your are going...It may be easier to do before we spend for the 15' conversion....your logic is on point I think! We were already planning fuel cell down the road along with some other stuff..

I would love to be around 31-3200lbs

Sorry to ask a question off topic.

Thanks for replying!

[Motorboy8769]

I got my answer and then I went off topic so no worries man. That is my plan i can’t see spending 7k on a irs setup for drag racing. If it was in to twisty turnies then that’s different.

[WHAMMO]

7200 here. Hitting 7k on a regular basis cause it sounds so sweet. 5k miles so far so good. TSP 231 236 on 111.

[Russell James]

Valve weight plays a big role.

Heavy valves...like stock intakes in an L99 or LSA...I wouldn't go anywhere near 7000. An LS3 comes with lightweight valves stock. Shops with a Spintron machine will know what valve and spring combinations will work 7K+.

Its much more than just the cam. It's also a question of valve weight...then components that have been tested together that are still stable at that target RPM.

[Dbunch9]

Originally Posted by Motorboy8769

I don’t know exactly what a Bare cradle weighs. Im hoping for 100lbs off maybe more I will have smaller and lighter brakes on the back plus a couple lbs lighter rims. Plus to do he 4 link I have to use a fuel call so I may Lois a little ditching the factory tank.
Once I get a cage in the car I’m going to cut all the un needed double wall steel that they cut off of the copo. They are 2900 dry I believe.

Here is a pic of the scale
Attachment 923412

Can I ask how the hell you got the weight down so much

[rebelyell22]

How high can you spin a stock LS3 without it grenading?

[Motorboy8769]

Originally Posted by Dbunch9

Can I ask how the hell you got the weight down so much

I took out everything not needed a.c. front and rear crash bars carpet padding stock hood seats wiper motor washer fluid tank. I was going to take door bars out also but that looks like more pain that it's worth for a couple more lbs so I took out the door insulation while I was in there.
There is a weight reduction list I went down and took out Everything free and wanted to keep it looking nice not like a gutted civic....

[acammer]

On the subject of RPM I read something very interesting the other day that makes total sense, but I'd never thought of before. This will probably be old news for most of you, but if it helps somebody else whom is taking their SBE up into the stratosphere then it's worth sharing.

The subject was rods/ rod-bolts stretching and failing under high rpm, and what you can do to protect against that. Closing the throttle at high RPM is hard on the rod and rod-bolts because you take away the cushion of air resisting the rod trying to kiss the head under compression. You have no such cushion on the exhaust stroke, so when you take it away on the compression stroke as well (such as by closing the throttle quickly while still at 7000+ at the end of a quarter mile pass and leaving the car in gear) you double up those extreme stresses where the rod has to stop the pistons upward momentum and drag it back down.

It's really simple - but I'd never given that much thought. It's a pretty easy practice for me with an M6 to make sure I clutch in and then grab neutral at the end of a pass. Auto guys it will depend on the trans (some don't like to be stuffed into neutral at high speeds/rpm). Just stuff to think about as we're pushing these components in the stock bottom end further and further beyond their design envelope.

[SSE 4 2SS]

Originally Posted by acammer

The subject was rods/ rod-bolts stretching and failing under high rpm, and what you can do to protect against that. Closing the throttle at high RPM is hard on the rod and rod-bolts because you take away the cushion of air resisting the rod trying to kiss the head under compression. You have no such cushion on the exhaust stroke, so when you take it away on the compression stroke as well (such as by closing the throttle quickly while still at 7000+ at the end of a quarter mile pass and leaving the car in gear) you double up those extreme stresses where the rod has to stop the pistons upward momentum and drag it back down.

Motorboy, (OP), nice ride. I like the weight loss program and the effort to this point. If you have not gotten air under the fronts yet, you're damned close..

As for the information above that I quoted... I would like to know who wrote this information and what the context was other than strictly a SBE motor.

1. I wouldn't think in most cases the SBE for the Camaro specifically is built to the minimal clearances this is implying. I would think a person would more likely strike the piston with a valve than crashing the piston into the cylinder head.

2. I can stomach that you might stress the rod's and rod bolts as well as the piston wrist pins, but I have to stipulate I've never seen windows created in block in the shut down area of a track... I've seen literally hundreds of windows created in the block on the racing surface, be it 1/8, 1/4, 1/2 the mile or on road and roundy round tracks.

3. I spin my LS motor up very close to 9,000 rpm (8700 rpm shift light) I usually manage to get off the throttle and shift by 8900 though I've run to 9,000 rpm quite a few times in lower gears since the motor pins up so fast.... It's tuned to that RPM. My motor is built to very tight clearances and I have a CAM with almost .800 lift. When dyno pulls are finished, the throttle is immediately lifted completely. When I finish a mile pass, the throttle is fully closed immediately after the chute is deployed fully. Full throttle to fully shut... I'm not saying there isn't any validity to the above story you referenced, but again I would like to know who the author is and what their legitimate background is.

4. I'll allow that an SBE set of rods, pistons and bolts may do lots of funny things. I never had any issues before I built my motor but it is possible as it is mechanical...

Video of a pull included with full throttle closure as the tires spun on the dyno at 8200~~ rpm... This was on moderate boost (20 lbs) making 1800 ish RWHP.

[acammer]

Originally Posted by SSE 4 2SS

Motorboy, (OP), nice ride. I like the weight loss program and the effort to this point. If you have not gotten air under the fronts yet, you're damned close..

As for the information above that I quoted... I would like to know who wrote this information and what the context was other than strictly a SBE motor.

I was referencing this article here:

http://www.enginebuildermag.com/2017...-rod-failures/

And some information that popped up in a Facebook discussion by GPI's Ryan Stevens:

"The reason rod bolts break on decel is because u kill the airflow at high engine speed and when the crank pulls on the piston/rod with the throttle closed it is much harder to pull the assy down in the cylinder.

It can cause the bolts to stretch and or break.

I program mine to still leave the throttle open some and clean shift to neutral so it doesn't engine brake"

In the case of Ryan Stevens quote it was directly relating to SBE LS3s doing big rpms on quarter mile passes.

And this thread here: http://www.yellowbullet.com/forum/sh...d.php?t=585314

1. I wouldn't think in most cases the SBE for the Camaro specifically is built to the minimal clearances this is implying. I would think a person would more likely strike the piston with a valve than crashing the piston into the cylinder head.

2. I can stomach that you might stress the rod's and rod bolts as well as the piston wrist pins, but I have to stipulate I've never seen windows created in block in the shut down area of a track... I've seen literally hundreds of windows created in the block on the racing surface, be it 1/8, 1/4, 1/2 the mile or on road and roundy round tracks.

Agree - I haven't seen SBE LS3s kick the rods out - and I agree that a valve-train issue is far more likely to occur first. There are plenty of guys turning serious (7500+) rpms on the SBE for hundreds of passes - so it's not like this is some "OMG if you engine brake the motor at 7500 it's gonna kick the rods out" statement. I saw Ryan's statement on Facebook, it made sense to me, so I dug around a little and found other supporting evidence that vacuum loading the motor at high rpm is hard on the rods/bolts. Is it too hard on it - apparently not because they are staying together. Still - if there are simple steps (like not hanging the revs high under vacuum) I can take to extend the service life of the SBE I definitely want to take them.

Seemed like relevant discussion for this thread.

Is that a SBE your referring to in the pulls to 9000 rpm?

[SSE 4 2SS]

Originally Posted by acammer

I was referencing this article here:

http://www.enginebuildermag.com/2017...-rod-failures/

And some information that popped up in a Facebook discussion by GPI's Ryan Stevens:

"The reason rod bolts break on decel is because u kill the airflow at high engine speed and when the crank pulls on the piston/rod with the throttle closed it is much harder to pull the assy down in the cylinder.

It can cause the bolts to stretch and or break.

I program mine to still leave the throttle open some and clean shift to neutral so it doesn't engine brake"

In the case of Ryan Stevens quote it was directly relating to SBE LS3s doing big rpms on quarter mile passes.

And this thread here: http://www.yellowbullet.com/forum/sh...d.php?t=585314



Agree - I haven't seen SBE LS3s kick the rods out - and I agree that a valve-train issue is far more likely to occur first. There are plenty of guys turning serious (7500+) rpms on the SBE for hundreds of passes - so it's not like this is some "OMG if you engine brake the motor at 7500 it's gonna kick the rods out" statement. I saw Ryan's statement on Facebook, it made sense to me, so I dug around a little and found other supporting evidence that vacuum loading the motor at high rpm is hard on the rods/bolts. Is it too hard on it - apparently not because they are staying together. Still - if there are simple steps (like not hanging the revs high under vacuum) I can take to extend the service life of the SBE I definitely want to take them.

Seemed like relevant discussion for this thread.

Is that a SBE your referring to in the pulls to 9000 rpm?

Interesting and thanks for the reply.... I wasn't trying to be argumentative, just wanting to learn....

I'll take some time and read the articles later on.... Thanks for posting them.

In re: your question about my motor spinning to 9000 rpm, and is it an SBE... Far from it...

Final assembly was by ERL
Heads are AllPro, 6 bolt LSW12 - 4
Jesel Valve train
Tool Steel Pushrods
Callies Big Block Crank, 3.9 stroke
Ultra Billet Rods,
Ross Racing pistons, with ceramic tops
Ductile Iron Sleeves
Block is girdled and half filled
Dry sump oiling,
10.5 / 1 compression ratio

ETC...

This motor is designed for 9,000 rpm's, and more but we stop at 9K max.

[acammer]

Originally Posted by SSE 4 2SS

Interesting and thanks for the reply.... I wasn't trying to be argumentative, just wanting to learn....

I'll take some time and read the articles later on.... Thanks for posting them.

In re: your question about my motor spinning to 9000 rpm, and is it an SBE... Far from it...

Final assembly was by ERL
Heads are AllPro, 6 bolt LSW12 - 4
Jesel Valve train
Tool Steel Pushrods
Callies Big Block Crank, 3.9 stroke
Ultra Billet Rods,
Ross Racing pistons, with ceramic tops
Ductile Iron Sleeves
Block is girdled and half filled
Dry sump oiling,
10.5 / 1 compression ratio

ETC...

This motor is designed for 9,000 rpm's, and more but we stop at 9K max.

No worries - I too like a good discussion - it's definitely relevant to this thread. Let me know what you think when you get a chance to read through some of that stuff. It makes good sense to me. Not sure that it matters a ton for the average heads/cam guy. I know my new combo is gonna want to shift in that 7200-7400 range. I should be able to trap at 6500 on a 26" tire - so it's not like it's gonna be hanging real high at the big end anyways. If I could get more gear in a stock rear I would.

Pretty neat seeing your wild setup with a clutch hanging off the back!

[SSE 4 2SS]

Originally Posted by acammer

No worries - I too like a good discussion - it's definitely relevant to this thread. Let me know what you think when you get a chance to read through some of that stuff. It makes good sense to me. Not sure that it matters a ton for the average heads/cam guy. I know my new combo is gonna want to shift in that 7200-7400 range. I should be able to trap at 6500 on a 26" tire - so it's not like it's gonna be hanging real high at the big end anyways. If I could get more gear in a stock rear I would.

Pretty neat seeing your wild setup with a clutch hanging off the back!

I looked at the build information of your car in your signature.... I bet with those rear gears the car launches pretty well already... though we all want more...

I went the other direction and run 3.07 rear gears.... and in standing mile racing I hang on a lot of RPM's for quite a while... Especially in 4th and 5th gear.... Throwing 2,000 plus RWHP against the driveline for a half mile is tough on EVERYTHING... As far as launches.... Imagine a battleship in thick mud... Yeah, it launches harder than my car... My power band is 6,000 to 9,000 rpm, and with my gearing I'm doing about 60 mph at the 1/8th mile... and then I'm 145-150 at the 1/4 mile... between 180 and 190 at the half and 225.8 so far at the mile... Car has a lot more, but we have to get everything working together and toss in the driver MOD...