If you’ve been following our G37 Sedan project it may seem like a forgone conclusion ending up with a Vortech V3 SI supercharger on our car. It’s a bit of a cliche in the automotive aftermarket to say I honestly planned on installing an intake and exhaust and maybe some wheels but here we are 4 years later with a supercharger and a built transmission for a G37. Quietly we always hoped something like this was possible but there’s all sorts of reasons why big projects like this don’t work out.
Being a kid before the turn of the Millennium
As a kid growing up in the 90’s I read just about every car magazine there was. Back then the Japanese halo cars like the Supra, 300zx and RX-7 were getting a lot of attention making around 300hp which rivaled the normally aspirated domestic V8’s of the time with about half the engine displacement or much less in Mazda’s rotary engine. The witchcraft taking place for the high horsepower and relatively small engine size was thanks to turbocharging and I became obsessed with the idea of owning a car with a forced induction engine.
I ended up turbocharging my SR20 powered B13 Sentra like many of the other writers here and had a ton of fun with that car. As much fun as it was, there were traction problems putting that much power down to the front wheels with skinny 205mm tires. Eventually the car was sold and life went on without forced induction.
The 370z and G37 debut
Enter the 370z and G37 and the VQ37VHR engine with Variable Valve Event and Lift (VVEL). Pumping out 332 hp @7000 rpm and 270 lb-ft of torque @5200 rpm out of 3.7 liters with a normally aspirated V6 engine. This exceeds what was done previously in the Z with turbocharging. Keeping the engine normally aspirated also kept production and overall vehicle costs down. However, the enthusiast market had a bothersome itch of wanting to know what’s possible if forced induction was added to the VQ37VHR engine.
Vortech’s centrifugal superchargers
Vortech superchargers founded in 1990, made a name for themselves in the automotive aftermarket focusing on centrifugal superchargers for Fords and later expanding to other car and truck applications. Today, nearly 30 years later Vortech continues to be a leader in the centrifugal supercharger compressor design.
Even if you’ve been around cars all your life you may be asking what is a centrifugal supercharger and how does it work. Flipping through a book on supercharging from Corky Bell and paraphrasing; simply put a centrifugal supercharger uses a pulley driven by the engine belt to move the impeller inside of the compressor via a set of gears inside the housing. The impeller draws air into the compressor housing literally compressing the air. This pressurized air moves though the diffuser and to the engine through charge piping provided in a supercharger kit. The look of a centrifugal supercharger is a lot like a turbocharger. The difference is a centrifugal supercharger is powered by the engine crankshaft and a turbocharger is powered by the exhaust gasses of the engine.
13 comments
Superchargers are just so neat, and not as popular as turbo charging as of late… Why is that? We need more article/project cars with superchargers. Looking forward to updates!
I personally would like to see an article with some sort of LSx powered drift car with one. Setups with air to water intercoolers, as well as some of the big block setups pushing 1000HP e.g. big iron drag cars.
Glad you liked the article! I’m looking forward to making more progress.
Our experience and exposure to various forced induction builds of course is subjective. There are a lot of reasons I chose to go down this particular path. The primary reason is that it was a proven path many had gone down before. I’ve gone down the other not traveled path and ran into headaches I didn’t want to deal with this time Turbo Sentra SE-R.
There has been enough learned since the time the original Stillen supercharger kit was developed to make some various upgrades like the supercharger compressor and air to air intercooler that seemed really interesting to me personally. I could have had similar discoveries down the turbo-charging path as well. There are a lot of forced induction options for the VQ37VHR just like there are for the LS motor. I was also drawn to the low noise of the Vortech V3-SI supercharger because of the low noise and the turbo-charger like peak efficiency.
I’m not trying to be evasive but you can build a turbo or supercharger setup to build power down low in the RPM range or up high if your shooting for huge power numbers. Again it’s a subjective choice. I was trying to find that sweet middle ground given that I’m forced to use 91 octane pump gas and I’m pretty much maxed out on a 10.5 inch rear tire to put that power down.
I’m not an engineer but generally speaking drift cars spend a lot of time at high RPM’s where turbo chargers are really spinning and make the most sense with all those exhaust gasses flowing. Those ‘big iron’ drag cars need to make immediate power off the line and that’s where those roots blowers really shine.
I don’t really like them for drift cars, not enough bottom end. Everyone who runs them in FD also has to run nitrous to improve the bottom end.
I feel centrifugal superchargers are much more suited for Renesis engines due to their aversion to backpressure and how choked the side exhaust ports are in general. Whereas it’s as if the old school 13B (non-Renesis) rotaries w/ their peripheral exhaust ports were made to be married w/ a turbo.
How come I rarely see any Rotrex builds? I love centrifugal supercharger but most builds I see that utilise them use a Vortech. Not knocking on Vortech of anything, I just wanna see a build employ Rotrex’s largest s/c; the C38R-112.
I’m more of an occasional lurker on the 370z forums only going there when I need to. I did read a few threads in my research phase about a company named GTM that was using a Rotrex centrifugal supercharger. It seems there was some trouble with customers getting their kits built or maybe it was just people on the internet complaining. Sorry I can’t be more helpful but I’d rather not insert myself in other’s battles.
The three companies I looked at that offered air to air intercooler kits for supercharging the VQ37VHR all use the vortech supercharger. I went with Vortech since it has been done many times before both with these air to air supercharging systems and the Stillen air to water supercharger kit.
Hmm, I guess it mostly just comes down to the availability of kits for the application in question, which Vortech seems to have the advantage in that regard. That’s a shame cuz I think the Rotrex units are very well engineered, especially its drive system. If only more people would do custom builds instead of just buying kits. I get that it’s the easier path to take and is a proven solution in many cases, but u learn so much more going thru the process of designing and fabricating a FI build from scratch imo.
Top gunz new supercharger kit runs the cr38 rotrex coming soon 😎
Nic,
Being the nerds we are here we went pretty far down the rabbit hole of Forced Induction for the VQ37 before pulling the trigger. I do remember there was a company (now defunct) who did end up going with a rotrex supercharger that I read about on the 370z/G37 forums. I do kinda hate forums at times though because more often than not in order for one thing to be good the other has to completely suck. Then the debates ensue for one argument vs. another. I did end up talking to Top Gun (I think his name is Aaron) early on and at the time he didn’t have a kit for the sedan like our project. He seems like a stand-up guy and other people in the business for selling parts in the automotive aftermarket held his work in high regard. We’re not done with our project yet. It just got put on pause like many things did with COVID.
I was going to get the Soho a2a kit but now everyone is waiting for top guns dyno run in a few days to see how his new cr38 kit will do, I’m in Australia and it’s so much cheaper to buy from the USA , over here 99.9999% of people just do intake and exhaust and call it a day on the 370z so most workshops don’t want to deal with you unless you shower them in cash
that ought to be interesting since I’m sure he has other dyno charts to compare from the old kit.
I’m curious to try and fit a larger air filter on our project because all of the air-to-air kits I’ve seen use the small harley davidson air filter. I just don’t feel comfortable running a turbo guard on a street car in dusty Phoenix.
I’m with you on the filter
Thats another nice touch to the the new rotrex kit from Aaron it utilises a large k&n without any restrictions in the intake pipe
I tried looking for information on it after your last comment and it didn’t look like the kit was publicly available yet. Now I can see it there.
https://www.topgunspeedworks.com/nissan-370z-parts
There’s an awful lot going on in that wheel well already. I need to get the help of a fabricator so I can pound my chest with an air filter on 😉