3R1$C

Here two examples, spinning it to 20krpm and 22krpm. The last column is the 21 PSI limit according to this screenshot from CI which contains the recommendation from Magnuson.

The 21PSI limit require a short block with at least 360CUI for 20krpm which will result in roughly 810RWHP.

The 21PSI limit require a short block with at least 397CUI for 22krpm which will result in roughly 890RWHP.

My conclusion is that if you want to spin the heartbeat to 22-23krpm, you should chose a short block with 427CUI to retain some reliability with the supercharger. Further to that, the charger is large enough for what you can get out of it with a standard small block LS engine, which is limited at around 454 CUI, supercharged versions to around 427CUI (427 LS Next from Shafiroff).

Chiselchst

You mentioned you have to abide by emission restrictions. Apparently you have some leeway? What are the requirements?

donnyt

There's a lot going on in here and a lot of overthinking. I know Unreal already mentioned it but Stock LS3s can take some power and it's a simple setup that many on here have ran for years. I'm at 780whp with a ECS1500 and stock LS3 internals. Detoxx ran his LS3 in the 900 whp range for years and beat on it.

CI GS

Lots of mental masturbation on this thread...

3R1$C

Thanks for the reply. Sure, you can make 1000 hp on a stock LS3 on the dyno a hundred times. Is it what you should do? This is like saying these parts make no difference and are all the same - there is a huge difference in failure margins between the stock and the aftermarket parts. No offense but I am not putting all this effort into a project that is just waiting to blow up. I rather not drive a year, not do holidays this year and get something done properly that will last.

The LS3 is not significantly more expensive than the built iron custom engine. The difference is effort. I have a brand new LS3 here and can easily sell that for good money. These racing short blocks are not that much more expensive. Good, honest, hard working American men putting it together for a very competitive price. Call Audi or Lambo for a short block and you will get nothing but junk at a price that you can only justify by prestige. There is no aftermarket that addresses the hundreds of design flaws that exist upon roll-out. The built quantities are too small to fix them ever - neither the factory nor the aftermarket will give a ****. The LS platform is the best engine platform in history and the dollars you pay for it are peanuts. The aftermarket in particular: I only wonder how these guys can make profit to survive. Seriously - look at the ******* effort in getting these parts made. This is ridiculous and I will spent the effort to do it properly.

3R1$C

That's what I am here for. I do nothing else all day long. It does seem that you are enjoying it a little to watch and read

Amongst the many uncertain things here - one thing is certain: you need more boost!

3R1$C

started on it / feedback welcome

Primary: 10-rib v-belt, ratio 1:2.3
IW 10% OD HB
3.50" 2pc 10 Rib L3 Pulley on jackshaft

Secondary: toothed HTD belt, ratio 1:1.5
80mm HDT pulley on supercharger
120mm HDT pulley on jackshaft

Chiselchst

3R1$C

AC Delco 12573024 tensioner included, bracket preliminary design completed






My fingers are hurting from using the mouse - spent 12.5 hours on this today.

3R1$C

EURO4 it is called. Some engine builders told me to just stick to the LS9 cam which has -20 degree of overlap. Emissions is basically all overlap. Some others told me that they would be a little more aggressive and reduce the overlap to -10 deg. Unsure what positive displacement cam would be suitable here.

The car will obviously have a different setup/tune on the street as compared to using it on the track/drag strip. Limit is 1000mg of CO per km and 100mg of HC (unburnt hydrocarbons) per km. I will limit boost to 3PSI and RPM to 5k on the street.

3R1$C

Can somebody help me with measuring the location of the heartbeat pulley? I have just done it roughly by comparing the CAD to pictures. You can chose any reference that I also have in the CAD. This would greatly help me as I have no heartbeat over here at this point in time.

Thanks

CI GS

I definitely don’t need any more boost. I’m at 13psi now and I only have 50hp jetting in the nitrous kit right now and I can take that up to 380hp, which is a hell of a lot more than I am going to subject the stock bottom end to. No amount of pulley ratio could make that kind of gain.

CI GS

What do you mean location of the pulley?

3R1$C

Deep, deep down inside your soul there is a voice that wants to grab your attention. That voice is whispering "m o r e b o o o o o o o s t".

Your reply is quite logical, I understand. I do not have the option for NO2, at least not in this car. It does sound like you also need one of these forged 427 LS next short blocks from Shafiroff.

3R1$C

The location of it with respect to the engine. The CAD I am doing is assuming where it is, but it is not accurate. Do you have a height measurement (from some reference) and a measurement to the left or right cylinder? Also the offset with respect to the harmonic balancer/drive belt. I unfortunately do not have the car/supercharger here with me otherwise I would just go over and measure. Do you see anything in the current setup that will not allow this to work?

3R1$C

Cool. I had a chance to talk to a bearing expert that I know from our development work (we do niche products for defense applications). We looked at bearings - they should really be ceramic/hybrid. We have used various bearings that we spun up to 50krpm in that size/required strength, but they are about 500Euros/piece - cannot use them at that price point. We are looking at affordable high-speed ceramic bearings at the moment...

This pulley setup should be versatile, and fitting other configurations/cars as well. I've done the maths for the pulley strengths and the toothed pulleys will be made out of stainless steel. There will be different ratios, the largest toothed pulley at the jackshaft will provide 30k rpm with the smallest pulley at the supercharger. I am not intending to run at that speed but the design will allow for it.





Last but not least: which supercharger applications can make use of this? I need to justify cutting a few of these parts. Commercially, this will be difficult-to-impossible as our workshop only does premium parts and that will come at a price but I will try...

Any input would be greatly appreciated.

Another question: Is there a 10-rib harmonic balancer for the Vette offset that has a standard diameter?

3R1$C

FEA on bracket done, plenty strong enough but changed a few details ...

Pb82 Ronin

Are you just bored during quarantine bro? Don't get me wrong...I'm all about making new stuff that benefits a community so I'm not faulting you here. But you're just after 800 HP...correct? This has been done HUNDREDS of times and can be done with simple mods and some extra cash. Why waste all this time on re-inventing the wheel (almost literally)?

How much power are you trying to make? Once you know that, you know what size compressor you need. None of this is hard...unless you make it that way.

3R1$C

Thanks for the reply. I'm after as much power as I can get out of a compressor that fits in the car. When you say it has been done a hundred times, then please show me a solution for a positive displacement supercharger that makes 20 PSI on a 427 LS motor and fits in the C6 chassis - where is it?

Unreal

Any Kong 2650 setup. Or any 427 with a tiny cam and restrictive heads, since boost depends on so much more than displacement.

Then again, those are WELL WELL WELL over 800rwhp. Also your calculations are missing so much they are out in fantasy land. I think this guy and the other keyboard calculation fiend are either soul mates, or the same person trolling us.