Whatever happened to twin superchargers?
 

Hi everyone –

I’m considering a 370Z Nismo purchase, but only if it can be upgraded to my preferred stage of performance. I wish Nissan offered a bit beefier platform to work with! (For example, it’s possible to get 458RWHP from a non-aspirated 3.6l Porsche GT3.) I owned a turbocharged car many years ago, a 1988 Mitsubishi Starion ESI-R (running 14.5psi), and while I know turbo kits have made significant improvements since then in terms of reliability, I don’t want to own another turbocharged vehicle. The car was fun to drive, to be sure, but it was a money pit, too, despite the high-quality competition parts I had installed. I didn’t like the lag, and the non-linear powerband as well.

I was intrigued by the possibilities offered by a twin supercharger on the Z, but after using the Search feature on this board extensively, I discovered that there are no new threads for this kit…the most recent seems to be from about three or four years ago. There is only one TSC build listed in the sticky, although I thoroughly enjoyed reading his excellent writeup: http://www.the370z.com/members-370z-...a-project.html (I can only imagine how sad it was to sell this car after all that work!) I also went down the list of sponsors of this board to see who might be selling and/or installing twin units, but all I could find were one or two doing the Stillen single. Based upon what I’ve read, I won’t consider the Stillen. The quality of some of the parts is questionable, and the maps seem to be poorly-coded. I read the thread detailing the air-to-air conversion…holy cow…I don’t have the tools/experience necessary, and I know there are no shops nearby who could do this if I went this route. I also found the threads discussing the GTM/Gamma debacle. That’s certainly enough to give me pause about even taking a gamble on ordering parts!

If I do a Google search, I also come up with Vivid Racing and Horsepower Freaks selling what looks like the same twin-unit GTM (Modern Auto Performance?) offers. However, they don’t specify that it will work/fit with newer Z models (I’m assuming the newer models require different mapping). Are the units available for purchase now, unsold leftovers from the tooling several years ago, and just passed around from seller to seller via wholesaling? And where are the pro shops familiar with installation?

Are most enthusiasts just installing the TT kits for the most bang-for-the-buck and possible future upgrades, and not messing with the TSC kits because they don’t have the same potential? Or is there something else I’m missing? If I'm understanding correctly, it seems that SS Firehawk was able to see something on the order of 50-75 more horsepower at an equivalent psi over a single SC. I don’t race, drop the clutch, or otherwise pound a car, and am just looking for 450-475 RWHP with the stock exhaust on pump gas. (Not a fan of loud exhaust, or noisy blow-off valves, for that matter.) If I can reach my horsepower goal with 7-8psi instead of 10-12 from a single unit, then I would say it’s worth the extra money.

Thanks!

I'm still a big fan of supercharged Z's. The constant squealing, pulley, and belt alignment issues just left me jaded. Honestly, if you're serious about supercharging, Gamma seems to be doing better at delivering kits than GTM ever was. I would pay with a CC and be ready to cancel if they're late though.

There are some recent trends that could benefit supercharged Z's now. Billet oil pump gears and the ATI damper can allow you to max the supercharger by spinning the motor higher without grenading the pump. The ported TB's, ported uppers, and ported lowers will improve efficiency, ECUTEK is huge for tuning, especially with FI'd cars. We can actually tune to prevent blow through from too much valve overlap. Running Z1's shorties (they actually fit with the stage 2) would improve performance as well. There have been a couple GTM stage 2 kits come up around 550whp, I can't remember off hand. But now with E85 too, I think a properly built SC'd car can provide NA linearity, with turbo power (probably not more than 600whp though). I was just chatting with Elmo370Z about ho awesome it'd be to see how a high revving SC'd Z would perform.

Don't let your experience with older turbocharged cars turn you away from the concept. Things have changed a lot since the '80s. A Z with a properly sized turbo has almost no lag. Other than the initial spool-up, the powerband looks very similar to the NA powerband, only with 200+whp more.

It doesn't matter what kind of aftermarket forced induction you choose from a reliability standpoint. A turbo setup isn't inherently less reliable than a SC setup. It's all in part selection, maintenance and the tune.

Honestly, before you drop a LOT of money for the car and mods, see if there's someone local to you with a FI Z. A ride in both would make it a lot easier to decide. Post in the appropriate regional subforum here and see if someone will take you for a spin.

You are taking 28 year old technology and an inline 4 cylinder car and comparing it to todays tech and a 3.7 liter v6. Yes, i have rode in 4cylinder turbo cars and yes they are rediculously laggy, especially when the turbo is oversized to make some sort of decent high end power. These 370Z's with appropriately sized turbos have very negligible lag and that large displacement gets that turbo spooling up quick. You really need to go for a ride in one.

Also, I'm not trying to push you into the stillen setup with my A2A kit but had to chime in on the statement that you dont have a shop that could install it. If thats the case then dont buy ANY turbo kit either since they are way more complicated to install. 80% of the guys buying the upgrade are doing it in their garages. So if you dont have faith in a shop that does that for a living then i wouldn't take my car to them for anything at all.

The twin SC kit (if you can get one and Gamma doesn't GTM you in the ***) would be a hell of a lot more involved than a Stillen kit with the A2A setup or a BP single turbo kit.

If you want DIY boost, I second BP's kit. Cost efficiency, yes, it's the most economical of the turbo's, but one of the best available. Saving on labor is a bonus. Especially for the power you want, it would spool up quickly. I don't have to mention Fast Intentions kit, it speaks for its self as to the power those things make. I agree with Chuck and Topgunz tho. My "like" button is broken

With all the improvements over the years there is little reason to do twin anything besides show and extremely high power levels. A well designed single SC or Turbo can put out the results any twin kit can for reasonable power levels as both the BP kit and the A2A setups have proven.

Gamma has the twin SC kit for sale on the website... just FYI. It isn't cheap though!

Also, there are guys with a lot of miles running 600+whp on stock blocks on E85. That's plenty beefy.

Thanks everyone for your helpful responses and experience! My thought was, if I went this route, to have a car fitted/tuned in Atlanta (5-6 hours from here). But having owned a car with a complex tune before, I understand the need to have a trusted shop locally for "issues." Based upon what you all are saying, perhaps the inherent liability gotchas would prohibit a sane person from taking this on in a location like mine.

One of the things I thought I understood about the TT cars was the difficulty in doing routine maintenance. Everything is up top with SC engines, and while tight, doable without dropping the tranny or engine-out? Did I get this right? The photos of everyone's engine bays blows me away! There's hardly room in there to squeeze a hand or wrench!

I can just picture a local mechanic with a car like this on a lift, with a beer in one hand and scratching his head. "Ya said the oil filter was where?" :eek:

When I had my Starion, I used a bleeder valve instead of a wastegate, primarily because I didn't want the pssshhh. Delicate and risky, to be sure, but it worked out OK. A wastegate on a TT would be a dealbreaker for me, and I know I wouldn't want to trust a bleeder valve on an exponentially more complicated and expensive engine/build. Anyone else use bleeder valves any longer? I think I read in one of the threads about an internal dump for a blow-off valve...perhaps an advantage for a quieter setup on a SC?

Is there an advantage, though, to engine response by having a twin unit instead of a single?

No argument there...but aspirated vs. non-aspirated. I would prefer NA, but the Nissan platform doesn't really offer the same potential as Porsche, for example.

Great idea to try to find someone locally -- I'll give that a whirl!

You can have a BOV plumbed back into the intake. That's not a huge issue. A SC kit is going to have a BOV open until you put your foot in it. It's not particularly quiet. No matter what kit you buy, access is a pain in the ***. There's just not a lot of room. I'm confused about the issue with the wastegates. If it's plumbed back into the exhaust, there's no additional noise. You can't have a turbo without a wastegate. There would be no way to keep from overboosting.

I substituted a bleeder valve for a wastegate, to eliminate the noise. It was continually dumping a tiny amount of pressure, to be sure, but wouldn't allow the pressure to go any higher than what I had it set for.

I didn't know about plumbing a wastegate into the exhaust...no one thought of that in the '80's! That might be an acceptable compromise.

I think you are confused about the difference between a wastegate and a blow off valve. A bov will make the pshhh sound and release pressure in the charge system. Wastegates bleed off exhaust gas only and an open dump wastegate doesnt make a Pshhh noise.. It goes. BBBBBRRRRRRAAAAAPPPPPPPPP!!!!!!!! and will blow your ears out and anyone beside you. But, it does sound beast mode.

I rode in another fellow's Starion years ago (and was running a lot more boost than me), who had a wastegate, and it made that psshhh sound every time it opened/dumped. But maybe you're right...perhaps I'm getting terms confused, possibly because the tuners I communicated with at the time used the wrong terms too.

The sound you described would drive me crazy!

I think your confused about what car you want.

You want over 400whp N/A. You should look into a new mustang 5.0 or a camero.

I hate "Detroit iron"...lol! I really don't like V8s at all -- they're unbalanced, and remind me of a pickup truck with headers at higher RPMs. Hate the styling that comes out of Detroit, too. And don't get me started on the poor craftsmanship (if you can call it that) and reliability. Not that other brands are much better anymore...

I prefer a more refined engine, and if I could afford a V12, would definitely go that route. Used to be, years ago, there were appealing, affordable sports cars with manual transmissions. Nowadays, that's all changed. The "short list" of cars I could live with...is...short....

Mustang gt350 then. Balanced flat plain ferrari style v8.

But just to address your concerns and complaints, the Z ain't the car for you

I won't argue with you. But there's NOTHING "Ferrari" about what's in the GT350. Not even close.

Get a Q50 red sport and a tune and make your wrapped out 485hp with stock components and zero lag plus awd.

A four-door family sedan that weighs 4,000 pounds??

You guys are killing me! This IS a forum for Z-cars, isn't it?

Yeah, I had a baby. Guess my taste changed.

How about a Miata?

LOL! I hear ya!

I don't like ragtops, and Mazda's engines are even wimpier than Nissan's. (We have a 2016 Mazda3.) My dream car is a three-pedal LP640, but those are like hen's teeth, even if I did have the dough and could convince the wife...

He's talking about ooooooooooooold technology.

OP, get a turbo kit and go have fun. I'm surprised no one has suggested the AAM TT kit. Yes, it's more expensive, but solely based on the turbos they use, they claim to reduce lag even further than other setups.

Also, you need to catch up with modern turbo technology, and not stuff from over 2 decades ago! :D

a huge V8 spinning to 8000rpm and making power all the way to redline IS a lot like Ferrari.

Guess I'm not your typical "boy racer" -- maybe more in a Paul Newman kinda way! :driving:

OK, you all have convinced me to take another look at turbos. I'll have to ejimicate myself on the new tech. Question: what sorts of things could I get away with limiting the boost to, say, 8psi, that wouldn't be prudent at higher levels? Stock exhaust, or no? Still need bigger injectors and pump? Other things?

No matter what kind of forced induction you do, you'll need bigger injectors and pump. Not to mention the clutch, gauges, tuning, etc. You can run a stock exhaust with the Boosted Performance kit, but you lose the cats if that's a concern to you. It'll be a restriction, but the car will still be fast.

I am feeling like you are a SC guy more than a TT guy. But, I see no reason to mess with the twin SC.

Install, setup, and tuning. These factors, more so than your decision in which system to use, are what is going to determine how well this plays out for you.

Your power goals are conservative, well within the reach of any choice in forced induction, and well within the safe limits of the factory engine.

All aftermarket kits leave things open to interpretation for the installer. The install and setup will make-or-break the whole experience for the user. Done with an attention to detail, and tuned correctly, you can very possibly have no perceivable increase in maintenance for the first several years.

I have the GTM stage 1 SC and recently ordered the Stage 1.5 upgrade.
Aprox. 475RWHP +-.
I have sent several emails and phone calls to Amin & Omar at Gamma.
They were very prompt to return emails and always answered the phone.
I ordered the kit about mid November, paid by CC and was just called by Omar to tell me the kit is shipping today.
Will update once I receive the upgrade kit.
I have had no issues with the stage 1 kit. Relatively easy to install and like the quality of the parts.

And they are in his backyard..

Thanks everyone for your suggestions and experience! Very helpful! 475rwhp would be awesome! I checked the fitment for the kit, and it says 2009-2013. What about later models?

AAM is in Maryland...I live in the Florida panhandle.

For some reason I always thought AAM was in Florida..

Which kit for late models?

please let me know how your transactions goes Kentmo. I had high interest in the SC until I joined and found out all the negativity surrounding them.
Ry

Do you mean newer? They one drop down is for 13+ so would include up to 16 models I would assume. I want to see if anyone has experience with these. When I called they said the original CATS could remain, but from the pics i see it uses their own exhaust manifolds and eliminates the CATS.

In my opinion, that negativity is blind. I bought my TT kit from them and they took good care of me... I have not yet seen anyone have a bad experience since Gamma bought out GTM.

Feel free to PM me if you have any questions about my experience.

GAMMA invested more money into GTM's inventory issue. They can at least deliver within an appropriate timeline, but most of their stuff now costs more money. If they're going to charge more money, they can upgrade the Chinese made components to higher quality pieces from the US