The MAIN point of the supercharger in a twincharge set up is to prevent lag from a massive turbo that would take a year to spool.

(Hope I worded that right this time)

 

"prevent" lag? like zzp's setup the SC runs until x rpm, say 3k then the bypass kicks in and the turbo takes over. Or so I remember from reading....

 

procharge that ****

 

Yeah pretty much.

 

you made it sound like the SC powers the turbo...sorry if I misinterpreted your statement.

 

The stock turbo on the LNF already provides much more low end torque than the M62 can. Adding a supercharger on the LNF would not provide any gains. If you swap out to a big turbo for serious top end then adding the blower would provide benefits. Another route would be to run sequential twin turbos. Add a 62-67mm turbo along with the factory LNF turbo and operate it similar to a twincharge setup except you would be bypassing the LNF exhaust wheel once the 2nd turbo spools. You could also add in a bypass valve to equalize pressure on both sides of the smaller compressor wheel. We could set this up, but it would likely cost $10k or more including the custom fuel system that would be required.

Centrifugal supercharging an LNF would be a terrible idea. While it is far better than running naturally aspirated, centrifugals don't offer much compared to a turbo. While you might make a little more top end HP than you could with the stock turbo, your low end power would be literally cut in half.

 

Well, my thoughts on doing this would depend on the availability of cheap LSJ take off parts. I agree that spending $1000's of dollars on a supercharging setup for an LNF is a waste of money, as there are more cost effective ways to add power to that engine. However, take off stock superchargers can be had for ~ $300 these days, so it doesn't seem all that infeasible to me to be able to find an entire takeoff / salvage LSJ supercharging setup (supercharger, intake/intercooler, heat exchanger, water pump, throttle body, hoses, etc) in the $600 range, which then puts this project in 'why the hell not try it?' type of price range.

Then it becomes an issue of fitment and tuning. As far as fitment goes, I think the big question would be if it would clear the direct injection system on the LNF's. Someone above said it wouldn't, but has anyone actually checked this? I don't know anyone around with an LSJ, but I'd like to park my LNF next to one to compare engine bays side by side. If it couldn't clear, a spacer might be an option, and might not be that expensive to fabricate one up. Would you make a spacer between the supercharger & intercooler/intake, or between the intercooler/intake and the heads?

As far as ducting, the main issue would be rerouting the cold side charge air piping into the supercharger throttle body, which doesn't seem like it would be all that difficult a task. Other concerns I have here are would the bypass on the stock supercharger be too restrictive once the turbo gets spooled up, and are there differences between the sensors on the intake headers of the LNF vs. the LSJ? And could the stock sensors just plug back into place?

Assuming one could get the supercharger fitted in there, and the plumbing and heat exchanger in place, then the concerns would be tuning for it, and the fact that the LNF stock turbo's operational range overlaps the supercharger quite a bit. Tuning it for fuel is a big question mark, but the rumor mill is that fueling wont be as big a concern once the fuel pump pressure has been unlocked. Then, as far as the turbo goes, aren't some people upgrading the wheel inside the stock turbos? Are they upgrading the turbine wheel, the compressor wheel, or both? How feasible would it be to use the stock turbo, leave the turbine side alone, and upgrade the compressor wheel and housing to something larger? Once again, maybe using some takeoff / salvage borg-warner parts to keep costs down on this. Wouldn't this, in theory, move the operational range of the turbo higher up, so that the supercharger could provide the instantaneous boost down low, and the bigger compressor would provide bigger power up top?

 

Better off twincharging the LSJ, LNF is making enough power with out a supercharger to push it.

 

Power industries did it, and they won the best car at the tokyo autosalon that time also. I'm more interested in the twincharger setup for there SR20.