uedlose

I guess its all in what you want to do with the car. How much coin you want to spend. I have had both and prefer the turbo over the S/C. but there was a time I would have had the S/C over the turbo any day. till I got the turbo now I love the turbo don't get me wrong it has been a fight all the way from install to getting the tune right and I am still fighting with that a bit. but it is a real low 10s street car and I think with the tune up a bit better it will runs 9s without to much trouble. its a lot of street car. I run less gear with the turbo less cam and less timing and I get 15+mpg I am sure that will go up with a better tune and I have 83# hr injectors car runs damn near like its stock. that is just some of the things I could not do with the S/C and still run as fast as I am now. Not saying that it cant be done with a S/C but I couldn't. I don't want a race car I want a sick fast street car that I can enjoy and I am well on my way. its even quite I love it and wouldn't go back to a S/C. maybe N/A but that's it. but thats just me

duneking905

i was looking at a procharger f2 or a turbo kit from greddy

uedlose

LOL F2 that will get it done damn. how much base HP do you make? you do know that the S/C have a HP rating to run them. F2 is a pretty serious S/C if you where gone to run a turbo that was equal to the power abilities of that S/C I am sure it is gone to take 88mm or larger turbo. and it would help to start throwing more then 302CID at turbos when they get that big don't get me wrong you can make them spool but its gone to take some work and lots of tuning. do you have all the right parts in place for this much power? How fast you looking to go? you know when you get to the 9.99 et and 150 mph the price of this fun goes up big time. then the next large jump is the 8.50 mark and that is REAL MONEY cars. and both power adders the F2 or a turbo equal to it has the ability to run 8.50s in the right car.

duneking905

my plan was to build a 427 and then procharge it. but i've been told that turbos are good for top end power. one thing that i kind of don't like is turbo lag. but im sure that can be minimized.

OnyxCobra

The way the single turbo kits are routed (both headers thru the turbo) there is supposed to be almost zero turbo lag. It's not going to be like driving a turbo import.

Rajun_Cajun

Turbo!!! Trust me. I have ridden in and driven both s/c cars and turboed cars. My friend (cprstreetmachines) on here has a turboed 347 stroker. Hes putting about 480 to the wheels off of only 7lbs of boost and still gets about 15mpg. He put 500tq at only 4000rpm to the ground. It feels like you are in a jet when you are in his car.

As far as s/c cars go, twinscrews make mad bottom end/mid range power and tq, where as centrifugals make top end power. If its for the track, I would go with either a centrifugal style blower (i.e paxton, pro-charger, vortech) or a turbo. Kenne Bell makes a twin screw for our cars.


As far as me driving both cars, I would choose a turbo ANY DAY!

67mustang302

It totally depends on the setup and how much power and where you want to make it. When you start talking about serious power the single biggest obstacle you will ALWAYS fight is traction. Either setup can produce more power than you can stick to the ground.

That's where a centri supercharger has an advantage(other than cost). Since they only boost at higher rpm the bottom end torque isn't as insane as it can be with a turbo(which can reach full boost by as little as 2,000rpm).

Also, depending on where the power curve is you can sometimes run a bit more boost on a centri s/c than you can a turbo with pump gas. That's because cylinder pressure is highest at peak torque(mid range rpm), where detonation is most likely to occur. Turbos are making full boost before you get to peak torque and therefore boost through it, significantly increasing cylinder pressures(and also detonation likelihood). Centri s/c's are only barely starting to boost around peak torque, so the detonation likelihood decreases, and since an engine is less likely to detonate at higher rpm than at peak torque, you can up the boost on the centri(since it only reaches peak boost at max rpm. Again, it's going to depend on how the engine is setup though.

That's why a centri s/c car feels very "peaky," since they only really move air for the last few thousand rpm of the powerband, and that's also why turbo cars make much broader power curves with more torque at a much lower rpm. Turbos do rob some power in the form of an exhaust restriction, but a s/c robs a lot more since it's an accessory. Also, most modern turbos are more efficient than s/c's so they generate less heat which helps reduce detonation liklihood in that regard, and make more power.

In the end it really comes down to a series of factors. A car with more gear and less traction and higher mid range cylinder pressures while n/a will be better off with a centri s/c, whereas a car with a more mild gear and better traction and an engine with less mid range cylinder pressure(or more detonation resistance) n/a will be better off with a turbo, generally speaking.

Lb for lb though, literally for the same boost levels on the same engines, turbos will always make more power since the s/c robs a crapload of that power just to run. In extreme cases such as an NHRA Top Fuel car, it takes around 1,000hp just to run the blower. Turbo setups often require more fabrication and money as well.

Screw superchargers are a breed apart, and make very broad power like a turbo, but with the power robbing factor of a belt and they generate more heat. And roots blowers are 100+ year old technology(originally used as air pumps for things such as mine shaft ventilation). They work and are the cheapest, but also the least efficient of all the blowers and the most likely to detonate.

And as far as turbo lag, a modern turbo setup correctly won't have any lag that you'll notice. Turbos can easily boost as fast as the best belt driven roots/screw blowers, and in some cases even a bit quicker.

Remember though, that all this is just generally speaking. It's going to come down to the individual's setup and budget, and possibly fabrication skills.

FoxGT

Expense used for used will depend on if you know what you're doing or not. Some of my kits run quite a bit, some dont. It greatly depends on what the person wants & whether or not they're willing to go with used/rebuilt parts. On both sc & turbo kits I've built in most cases the kit itself isn't what kills the price, the fuel area is what does it & both have the same problem in that field. What parts you use will decide your kit cost, even little parts; would you rather pay $50+ for an oil feed line or buy a $15 -3an braided brake line? Built the exact same, yet one has a price tag like it's gold plated & that's just one simple part. It adds up if you keep taking the high road.
Sound's like an unfair match to me. Sounds like someone neglected to size them up properly or psi difference.
The bad part is, most people can build a more efficient kit than most of the popular companies with a little bit of research. Some people have done it & got before/after dyno #'s
I don't find turbo's harder to tune at all.
You can build one for alot cheaper that will last. I've built a twin turbo kit for a v6 that has been going for over 4 years now with zero problems other than a blown off coupler to the intercooler due to not putting the proper type of clamp on it which was fixed in less than a minute. And that kit lasting 4 years was built with almost 100% junkyard parts for a little over $700.
Singles have more lag due to a heavier rotating mass when comparing one larger turbine/compressor to two smaller ones.
15mpg is still relatively low for what it is unless the engine wasn't built to compliment other parts. Your friend should have no problem getting into the 20's if built & tuned correctly.
Screw superchargers are hardly a breed apart. While I will agree with you on efficiency being low on older models of the roots, I don't know any car company that's used the straight rotor design in some time. They are still built, but not so much for street cars. The 60 degree 3 lobes can be fairly brutal with a modified or aftermarket case. Personally I would take a 4 lobe 160 degree roots over a twin screw any day.

Turbo's will always have lag & will never boost as fast as a belt driven supercharger, especially the roots & twin screw not only due to them being positive displacement, but because they are tied to the crankshaft. If you floor it in a roots/twin screw the air gets compressed when it reaches the supercharger (or right after for the roots) whereas a turbo has to first get a high amount of exhaust gas energy which means you have to push the throttle, the air/fuel mixture has to burn then travel through the exhaust, & finally the mass of the turbine/compressor has to spin up to speed. Sure while at 5000rpm if you punch it you may only have .2 seconds of lag, it's still lag, & it's still noticeable. I'm not bashing turbo's I love them but imo when it comes to building them I prefer people to want a roots kit over turbo's due to getting to drive the car afterward. Roots imo make a more fun to drive car, but not a faster one. But for assembling; I prefer building turbo kits because I find them easier to build than s/c kits.

67mustang302

For the most part I agree with that. But depending on setup, you can have a fair bit of low speed leakdown with a roots or screw(if the blower is large for the engine) and lose some boost response as a result, and you can have a pair of very small turbos with a tiny a/r ratio that can respond quickly at very low rpm(but would be too small to make best top end power).

I like roots myself for their simplicity, but I wish more companies would start investing some technology into them. Most of them aren't as efficient as they could be.

redpony88

i like turbo's better, although i love the s/c whine. the blowoff sound is cool in my book.
also if you've ever watched turbo 5.0 vids the turbos have little to no lag time, we have 8 cyl pushin the turbo not 4
i myself am gonna get a turbo kit for my 95.