my vortech setup is running around 450whp and I agree fully that a turbo will feel faster around town. I'm pretty sure a 390-400whp single turbo car will feel like it's just as strong as mine...until about 5000 rpms and upward where mine will start pushing noticably more power

Most guys that drive in a vortech car and say it's not that great are driving stock-ish vortech setups with the stock pulley making 360-370whp. It's a different beast when you upgrade the pulley and add other things into the mix like 3.9 gears, cams, headers, light clutch etc etc


if you ever look at the turbo dyno curves, you'll see that from 2000-3500rpms, the hp and tq rise at a rate that mimic a 600-800hp car (if the curves were to continue upwards at that rate) except that after 4000 rpms it levels off dramatically after full boost to be what it is - a 400-500hp car. That's the big thrill with the turbo kits

SC cars feel more like big 400-500hp V8's without any of the thrill that turbos have. And yeah it is easier to control traction since it's progressive. If you're going to be running drag radials or slicks anyway though, then you might as well go for the turbo setup since you'll be able to hook that power up to the ground. Turbo setups are usually harder to control because of that 2000-4000 rpm range where the car is acting like it has 600-800 hp

the VQ35 responds the most to power/tq in the midrange where it's the most efficient. The vortech setup will only be able to feed a portion of the PSI to the engine at that range that a turbo can.


people with turbos usually lower their final drive as a way to get better traction, gas mileage, and less shifting and those are all great reasons, but it'll hurt your higher gear accelleration. Meaning if you had a 400whp vortech with 3.9 gears and a 400whp ST with 3.3 gears and you both were at 100 mph and started accellerating, the vortech would destroy the ST car with having over 16% more gear accelleration. Gearing is one of the reasons the Z doesn't do too bad at higher speeds against camaros and firebirds etc who have stock gearing because the Z's gearing is way more aggressive than the stock gearing on almost all LS1 based cars by about 10% for all the gears minus the overdrive gears

getting a 3.9 final drive with a single turbo is asking for wheel spin with street tires in 1st-3rd gear, where it seems to work really well on my vortech car

 

Gearing does affect especially the top speed, but who races from a roll on a 100mph? Bottom line if reliability is not a concern, a SC has no advantage on a Turbo, even with the sudden power on low RPM it's just a matter of learning who to control it. IMHO

For me Reliability is so important that SC is my first choice Go Stillen!!

 

the 100mph race was just an example since it becomes much harder to accellerate hard at that speed

 

The reason on downgrading the gear is to stay on boost much longer, so it doesn't matter if the gearing is lower but because your on boost longer the Turbo will still catch up. So far most people that I know just stay with what ever they have and not bother to upgrade the gear. why will it be advantageous for Vortech to upgrade their gears, I know your RPM will climb fast to get boost much quicker but that means you'll have to shift quicker and not stay on boost longer.

 

Thanks fellas, I appreciate the input. I looked up forgedinternals and will swing by there this weekend. Reliability is first and foremost as this is my daily driver. I'm not looking for anything extreme as I'm looking to only buy the kit, get a good tune and gauges, so 380 whp is good enough for me. Stillen...I hate the hood. HKS, looked at one they were installing at CPRacing and the SC only engages under full throtte. I love the pull of a turbo as I used to have one awhile back. If the Turbonetics ST kit is equal in reliability to the Vortech, then there's my answer. I don't want to run the risk of damaging anything with the torque of the turbo, so if it's that extreme, I might need to go for something more linear, ie SC. I want the benefit of good power in the 2500 to 5500 rpm band. After driving several loaners over the last 4 weeks, the automatics seem to rev smoother and faster to the redline than my 6mt. Around 6000 rpm, my car sounds truckish.

 

the vortech builds boost, it doesn't reach full boost then hold it - that's why more aggressive gearing works better with the vortech. You're always a few rpms higher in each gear and when you step on it, you get 10% faster accelleration into the high boost..

the saying about staying in boost longer is a boosted honda civic myth that doesn't carry over to the Z. It's not only wrong, but the the Z makes full boost at 4000 rpms at the latest anyway.

what you want to do is stay in your powerband - hp - where it's close to redline. Otherwise why don't racers drive the 1/4 mile in 3rd gear then shift to 5th to drop the rpms back down to 3500 rpms or whatever where they're making full boost and just drive that gear to redline? It's cause at 3500 you're making crap for hp. The tq is nice and all at that rpm, but hp is what actually accellerates the car due to the increased rpms while tq is how responsive it is.


If the goal was to stay in boost longer then we need to stop messing with the final drive and start changing the actual transmission gearing so that the rpms ALWAYS drop to about 3500-4000 rpms when you shift at redline. However you're not making much power at 3500-4000 rpms so it'll just slow you down.

By the time you reach the 4th gear or around 100 mph, the gearing could stand to be quite a bit shorter to help accelleration. However Nissan decided that people do care about gas mileage when they're on the highway - that's the ONLY reason the Z's higher gears are as "weak" as they are. The lower gears are way strong (probably too much for FI) because the car was designed with 287 hp and 274 tq originally. If Nissan could have made a 7 speed transmission they probably would have gone with that and made gears 4-6 shorter with 7th being the overdrive. Cause you otherwise normally spend more and more time in each gear as you get into the higher gears.



The big factor is as you reach higher speeds the air drag increases dramatically all the while the gearing is getting weaker and weaker that the car has less and less accelleration - so the top gears should be shorter and low gears should be taller in an ideal world where you want to reach say 160mph as fast as possible - yeah how many people do that etc, but it's not like you're ever going to drive to 184mph with the 3.36 final drive either


for reference, if you watch a video of a guy with a ST and 3.36 gearing (184mph top speed) running to 160mph it takes roughly this long if you time it:

1st 3 sec
2nd 2.5 sec
3rd 4 sec
4th 4.3 sec
5th 6 sec
6th 14 sec

ideally each gear would last about 4 sec or so

 

how much did they charge u?

 

I know you are set at Vortech but if you want power from 2500-5500rpm then Stillen will be a very good fit for you especially if you just want that extra power and do not intend to go 400+whp. Check the dyno of the Stillen and you will see that power is there from 2k RPM and the only flow is that it dies a little above 5500rpm which fit your power band. With Vortech you won't get all the power until you're above 4KRPM (Just like driving Honda must always be above 4K to stay VTEC), IMHO. I know sentry65 will post again and defend his Vortech again

PS
just be aware that with Vortech there is a fine print that the kit includes a gurgling sound like a marble in a can while in IDLE


OK, Stillen is no angle either coz you have to change the hood

 

Ok you can worship your Vortech all you want but give me a name who got to 11's with your kit? you can have all your Final Drive you want but the bottom line SC will never come close to Turbo. Oh, I guess you're familiar with Alberto and his 396whp - 400ft/lbs 11.98 @ 114. I bet this should be easy for you since you have more power than him with your 450-455whp 360-365 tq.

 

what's with the attitude? All I did was answer your question. Yeah whp for whp a turbo is better. But when you start changing final drives and have 60 more whp, things change a little. Not to mention my car has a lot more work done to it than albertos if you read my mod list. He's probably a better driver than me though and will be faster for that reason alone

if it makes you feel better, I can link you to someone with a vortech kit who does 12.4-12.7 consistently with an auto with 370whp on street tires - no it isn't Ben with the ATI procharger. This is another guy who can do 12.4@112 with 370whp on a vortech and an automatic and stock wheels shifting 500 rpms before redline. You can PM him for details

http://www.350zmotoring.com/forums/s...5&postcount=14



If he had a manual with stronger gearing, less weight, less rotational mass, and 80-90 more whp and some drag radials, I dunno you do the math but I think he'd hit 11's with not much of a problem. Alberto is a great driver, but a 400whp turbo isn't the God setup everyone makes it out to be that will NEVER be beaten by anything that isn't turbo. In the WOT range from 4500-6600 rpms a 460whp vortech setup makes a lot more power overall. And then you factor the gearing into the equation and the 3.9 will have to shift 1 more time than the 3.3 gears, but we're still talking about a 16.3% difference in accelleration

Even when talking about torque, ST cars make peak tq and hold it for around 3500-4500, then it starts dropping off pretty fast. A higher end vortech car might have 30 less tq peak that starts at 4000, but it holds it almost all the way to almost redline which is why the hp ends up being 50-60whp higher than a 400whp ST. The ST has the advantage with no doubt in the 2500-4500 rpm range, but after that a 450whp vortech car will start catching up to a 400 whp turbo car

 

I wouldn't throw Alberto's times in with the general public. He is an exceptionally good driver. I am sure if Alberto drove Sentry's car he could get it close to the 11's if not into the 11's.

 

I know Alberto is an exception and I just threw it out there. The original poster said that SC and Turbo are pretty even in HP, I just pointed out that they are totally different. As usual sentry65 came in and pointed out that on higher gears that his SC will trash a Turbo because of is upgraded Final Drive. sentry65 I know you have a good setup and you love your Vortech. Stillen, Vortech, Turbo all have different purpose and for different drivers. I want you to acknowledge that all kits have an advantage and no one is Superior on every field (Highway, Drag, Street). Peace I apologize for the attitude.

 

no prob, I've been advocating that each FI setup has it's pros and cons for a long time now.



I don't think the vortech is the answer for everything and in fact far from it. For people that have asked me, I've recommended ST and stillen and TT kits to all sorts of people depending on what they say their end goals are. I firmly believe turbos will be by far more fun out on the street than the vortech. But for people that don't have a good tire setup and want to run their bling wheels with skinny tires, the vortech is probably better for traction

Actually I still have thoughts of switching to a TT eventually someday when I build up the engine. Not sure if I'll stick with the vortech and go to the 2.87 pulley and have the shortblock bored out to 3.8 liters with darton sleeves or simply get a normal built block, sell the vortech and headers and get an APS tuner kit - each scenerio costs about the same so it's hard to decide right now. No one is running a 3.8 liter 540whp vortech setup right now that I know of, where 500-550 whp TT cars are pretty numerous. For the TT setup though, I really don't think I'd be able to put 500-600 tq to the ground and make use of it without drag radials or a really weak final drive.

I started out by saying the vortech feels like a big 500 hp V8 and a turbo - single or twin will feel like a 800 hp monster between 2500-4000 rpms, then level off to feel like a 500 hp V8. Turbos are for sure better in terms of power output and feel at the expense of more heat and less controllability (though manageable with the right tire setup and throttle control)

Sorry if I came off aggressive in my statements or anything to spark any flare ups. I think this all happened with me trying to explain why the 3.9 FD works great with the vortech and why the 3.3 gears work better for people with turbos, though it only seems to solve half the issues - and it isn't really about staying in boost longer but making the huge tq more manageable on the street with less wheel spin. People say they don't even notice the 6% less accelleration because they've made up for it with more traction. 1st and 2nd gear are more useable and they therefore get a better launch and end up netting the same trap in the 1/4 mile with 2mph faster trap speeds - and that's with 1 less shift than before, so that .2 sec of saving an extra shift was lost probably in 3rd and 4th gears not being as strong as they once were.

whereas the 3.9 is good with the vortech by helping 1st gear out since the vortech is weak below 4000 rpms, and gets you to redline faster to stay in the powerband, then helps with the higher gear accelleration where 4th and 5th would normally feel like forever compared to 2nd and 3rd.

I misread the 1st post by the threadstarter and though he was not going to be running gauges - and he is, so in that case I say to go for the TN kit as long as he can get to a dyno and make sure the tune is good and either mail the ECU back and forth or get a UTEC or Unichip or Emanage Ultimate and custom tune it right there on the dyno

 

I believe the tuner I spoke with, said they were running the ST kit with a Greddy emanage system.

 

http://forums2.freshalloy.com/showthread.php?t=151662