OK. I am buying a motor to play with. It is a VG30DE (non turbo zx motor for the uninitiated) Here is the only bit of information I need to know to complete my little experiment. Does the compression ratio in the VG30 motors come from the pistons? Example, the lower compression of a turbo motor comes from the pistons being "dished" or concave but other than that the pistons are the same (size in bore etc). Please let me know if this is correct. thanks.
Yes you are correct, the tt and na use pretty much all the same internals except pistons and gudgeon pins(thicker in tt) and a coupleof other minor things. The cylinder heads can be interchanged but I would expect a slightly lower power output using na heads on a tt, tt heads should flow like a mildly ported na head.
Thanks for that. The reason I am asking is because I want to supercharge this engine. To do so would mean decompressing the engine. Traditionally this would mean doing it via a decompression plate but if the motor can be decompressed simply by changing the pistons this would eliminate problems inherant in the traditional method. I have designed this setup so that it looks like a traditional SC setup with the supercharger mounted ontop of an extremely modified plenum and run from a belt coming from the belt array. There is a second way I have designed also which includes intercooling for the SC but I am yet to read info on gained advantage from intercooling a SC (been reading heaps out there, if anyone has any info let me know). Peace
Use a TT block and get a screw type supercharger rather than the normal lobe type eaton blowers. So much more efficient and you don't need to intercool them. It'll stick out of the bonnet too
Intercooler an s/c has the same benefits as an intercooler in a turbo application. Unless you can atleast 65% belt wrap on the s/c puley, you may need to look at going to a set of custom drive pulleys. Try to avoid the little toyota sc12 and 14's, they will work on the vg bit are a bit too small for any good power. I wold be looking at the s/c of a vs on blown v6 commodore, they are well sized and quite cheap. The other problem is getting it uder the bonnet
That is why I have designed a plenum to take it. The plenum design I have incorporates part of the actual plenum (butcher!) and the SC itself. I could go for a centrifugal style one alternately. SC14S and eatons are quite cheap. LOL. If I was thinking of using an eaton I would go for the M112 used in V8 engines. Is there a reason for using the TT block?
No benefit in using a tt block, they are the sme, I think what chris is getting at is they already have the lower comp pistons and higher flowing heads so less cost will be involved to rebuild.
Yep, that is what I was getting at Even with a butchered plenum it will stick out. You seen that one on youtube yet? SC14 isn't big enough for the expense. M90 or M112 wouldn't be too bad, but discharge temperatures at anything over 7psi is just stupid. 120deg isn't uncommon at high boost from what I've read about them. Screwtype supercharger FTW. Clicky
Ahh if only I had the money for a whipple! . . . The measurements for an m112 and the plenum I have designed should be clear of the bonnet line but if it works remains to be seen I would do the TT motor thing but Ive got another NA motor I can use already. If I could find a half shagged TT motor I would rebuild it and use that instead (anyone out there with a half f**ked TT motor they wanna donate to this experiment?). There is a place that I found that fabricate decompression head gaskets. You tell them what you want and they make the gasket for it, this is perhaps another avenue that could be used. My mission is always to have something that no one else has, thus the reason for wanting to supercharge a Z32 (I havent been able to find anything on anyone doing it, so if you have info please let me know) PS: havent seen the one on YouTube . . clicky?
If you use spacer plates or thicker headgaskets you'll srew up the fitting of the plenums. Just use a set off TT forged pistons in an NA block, you'll also need a set of TT oil squirters too as they directt the oil onto the piston pins differently than the NA ones do. You,ll also need a TT sump to hook up an oil cooler too. A bit of basic googling will throw up the differences between the TT and NA motors. Don't belive the old wives tales you will come across the cranks and con rods are the same, all forged
That was what my original thought was before I started posting. Use TT pistons in the NA motor. Looking at that YouTube vid of the guy that supercharged his Zed, he seems to have used a m90 or m112. That one obviously does not clear the bonnet so my calculations were probably incorrect. I wonder if Gonzo sells rice bonnets? JK . . . it can always be monted somewhere else, especially if it is going to be intercooled.
I know jack all about superchargers, but if you're into custom fabbing and want something that may clear the bonnet, here's some food for thought: http://i483.photobucket.com/albums/rr197/Horsepower_Freak/31102008128.jpg Obviously missing coilpacks, but methinks you could mount an s/c to one side of the plenum? Possibly over the coilpacks?. Maybe ditch the A/C and put a stupidcharger there instead?
That is the type of thing that I was thinking of. There are a couple of prospective places to mount a SC and I will find a way to do it. My father-in-law is an engineer so I can get stuff done and passed easily. I am gonna work on the NA motor I already have since changing to a TT motor would mean swapping the loom and everything. This way I can modify the NA motor with TT pistons and squirters, install the SC and drop strait into my car. It would be interesting to see how it stacks up against a TT. Since the SC has constant pressure at the cost of a little loss due to being belt driven, it has the potential to make quicker 100k times and better power across some of the range. Running at a constant 7psi or higher means that the bost will be there instantly with no lag, Better throttle response and if other things are done like lightened pulleys, flywheel, etc, the loss from being belt driven can be reduced to almost just a trade-off of power.
Hmm, not likely. You checked out the power consumption of the M90? It's a decent wack more than a UDP and fly will give you I hope you are only doing this for the challenge. It'd be easier and cheaper just to chuck some standard turbo's onto the NA block and run low boost. NA and TT harnesses are practically identical, only difference is the safety boost solenoids, which don't matter if you have a boost controller.
Yea i've checked all of the numbers and I am that things can be quite different when done properly. I dont want turbo, thats the point. I dont want what other people have, i want something unique. Being of the old school, I kind of like the power that a SC gives. The fact that a SC gives better throttle response is well proven (instant boost) there is loss from the belt of course but this can be minimalized which I have seen done a thousand times on my father-in-laws hot/rat rods. It is all going on a motor that I got for cheap anyway . . ill still have both motors.
