Supercharged or twin turbo? Or single turbo? Performance differences/pros & cons

[cheapazz]

Looking into the future...waaaaaayy into the future at a forced induction upgrade. Which is better? I prefer S/C for power across the board but which is a better long term investment and which has better power? Which way should I start pushing on my wife about?

[smockers83]

Forced Induction area?

I think twin turbo gets you the most power, but I'm no specialist in this area.

[tollboothwilley]

Turbos spool up much faster than superchargers so you will generally have higher gains throughout the RPM band while the supercharger will build up.

Twin turbos, additionally, will have almost no lag if properly set up.

I believe that superchargers are better on engines for longevity.

[cheapazz]

Superchargers are constant, there is no spool up time involved but I think as long as the S/C isn't set too high in boost that your right about the longevity and reliability.

[superchargedg]

Superchargers are constant, there is no spool up time involved but I think as long as the S/C isn't set too high in boost that your right about the longevity and reliability.

The stillen s/c(which i do not rec)has instant torque but suffers badly in the upper rpm's.The centrifical s/c's have no low end power at all but do have very good high rpm power(vortech,ati procharger).The single turbo is great for power but has a lag to it and they suffer from boost spikes(WHICH IS BAD),the twin turbos are the **** though.I had the the stillen s/c since mid 2003 cause it was the only kit that didnt blow every motor but since i went to the greddy twin setup i couldnt be happier.

[eZg001]

Is it neccesary to pull the entire engine in order to do a "Build"? I have been begun researching but wonder if a partial build would suffice. I am obvious not very knowledgable about engines...Still trying to figure out the diff. between a long block and short block.

Thanks

[C-Kwik]

There is nothing inherently better about the turbos themselves when considering a single or twin turbo application. Either can have similar boost thresholds and response. It really comes down to how well the turbos match. Large turbo selections are somewhat limited as they tend to built for certain types of applications. Using two smaller turbos can increase the choices available to you for a better matched system. A twin system in a motor with more than one bank of cylinders can have a small benefit of placing the turbos in closer proximity of the exhaust ports, but it's not going to have a significant impact on "lag". Turbo sizing will have a much more profound effect here.

Of course, in ultra high HP applications, two large turbos may be required to meet the airflow demands that a single turbo can not. But that's a different issue altogether.

[superchargedg]

Yes you will have to pull the engine for a rebuild.The diff between a short and long block are simple.The short block dosent include the cylinder heads.

[superchargedg]

That is somewhat wrong as a roots style s/c is constant but a centrifical s/c builds boost as rpms increase.The stillen roots style i used to have would have 8psi as soon as i mashed the throttle but my buddys vortech takes a little time to hit full boost and it reaches full boost near redline.

[C-Kwik]

I wouldn't call it wrong. The perception from behind the wheel is that there is lag. But the Centrifugal S/C will hit the max boost that is possible for the given Engine RPM as soon as you go WOT. So boost is instantaneous. Its simply not as much boost...

[cheapazz]

I was misleading in my comment, sorry bout that, I was refering to the roots type s/c......I just have a personal dislike for the vortech/centrifical types and tend to disregard them when talking about s/c in general.......MY BAD! I'm thinking a roots type would create the low end torque range I'm looking for. Sound right to y'all? I'm not building a racer, just a fast street car with the possibility of maybe going to a couple of local drags or scca events. But just mostly for my own seat of the pants amusement.

[joe603]

You will not get as much for the money with a roots type SC. (Stillen) You have to not only pay for the SC and tunning, but you have to get an aftermarket hood or hood scoop because the roots type sits on the intake.

Even for a stage 4 Stillen SC, you will have less power than a Vortech or a single turbo.

However, to each his own! Post up pics with whatever you decide to go with!

[superchargedg]

A big +1 to this comment and as a former stillen owner please dont waist your money on that kit.But you do not have to have the stillen tuned as it comes with a pre tuned ss box that is locked.Stillens tune is ultra conservative as it runs rich and pulls a lot of timing and i think that is why my greddy twins on low boost just would destroy my stillen stage 4.

[C-Kwik]

Stillen put a lot of energy into two things. Reliability and CARB legality. As a result, their tune is generally conservative. But a large part of the lower power output is the fact that the type of S/C they use is generally not as efficient as turbos and uses the power output from the crank to run it. A turbo system (reasonably well matched) on a similar tune and with similar boost levels would likely yield better results simply as a result of being more efficient and exhaust driven.

[cheapazz]

OK, But with the TT don't you lose your cats?? How does that work? What is done with the O2 sensors? Is it like with a test pipe, just put 'em in and hope no codes pop? Is the system 49 state legal?

[C-Kwik]

The Turbo manifolds and turbos are located ahead of the cats. Its a tight fit, but to my knowledge all the TT's have been able to retain use of the cat. Turbonetics had to delete the cat as the plumbing to the turbine attaches where the cat would be. I believe they do offer their kit with a Cat, but it would simply be an aftermarket cat. Not sure where they located it and it definitely would still be illegal...