Bigger turbo is bigger lag?

[astigracing]

i don't know a whole lot about turbos, is it true bigger turbos create bigger lag? if so, why? if not, why not? i'm curious because my friend built a twin turbo c32a motor (acura legend) with t28 turbos. he said that if he uses bigger turbos it will create bigger lag.

 

[Quin]

Bigger turbos have bigger wheels which take longer for the same amount of exhaust to spool up. There are ways around this, but generally, bigger turbo = more wait for power, but more power when it gets there.

 

[astigracing]

Bigger turbos have bigger wheels which take longer for the same amount of exhaust to spool up. There are ways around this, but generally, bigger turbo = more wait for power, but more power when it gets there.

what other ways around this? appreciate the help!

 

[88YotaTurbo]

increase the flow of the motor and you won't have to wait so long..
The faster you can rev to the power the more time you'll have using the power.

 

[Quin]

Nitrous, methanol so you can run more timing, head work

 

[bgrieger]

put them on the bigger motor they belong on...

 

[bountykilla0118]

put them on the bigger motor they belong on...

I don’t get what you are saying ..... are you saying that 3 or 2.5 liter inline six is not big enough ???? If you are LOL you should be quiet. Think 1jz, rb26, 7m, and 2jz when modded right those engine perform really well. Search and you find out.

But modern turbos aren’t that bad. How quickly does your motor get to 3500rpm? I would say rather quickly and keep in mind people ask about full boost which can be misleading to someone who does not really understand that even though you have not reached full boost, you will still be boosting. 10psi on the stock turbo is not the same as 10psi on something like a 67 or larger. You will be very surprise at the difference in acceleration even when you haven't it "full boost"

 

[buckshotglass]

Lag is that short period of time when the car next to you thinks they are going to win.

 

[Doward]

Lag is that short period of time when the car next to you thinks they are going to win.

QFT, and going in my sig!

There is more to 'lag' than just what size turbo you have. Dual ball bearing setup will decrease spool time. Ceramic turbine will decrease spool time. A standalone with proper timing will decrease spool time.

 

[bgrieger]

I don’t get what you are saying ..... are you saying that 3 or 2.5 liter inline six is not big enough ???? If you are LOL you should be quiet. Think 1jz, rb26, 7m, and 2jz when modded right those engine perform really well. Search and you find out.

No, I'm saying if the lag is too much for the turbo you have, you have 2 real choices get a smaller housing, or get a bigger engine. If you've tuned it properly, and are still unhappy with the lag, all the monkeying with the existing formula is nothing more than a bandaid.

 

[Poodles]

bingo

modern turbo design is more efficent and have lower lag with broader powerbands and a larger area on the compressor map...

if you have lag, you're not in the right gear IMHO...

 

[tte]

No, I'm saying if the lag is too much for the turbo you have, you have 2 real choices get a smaller housing, or get a bigger engine. If you've tuned it properly, and are still unhappy with the lag, all the monkeying with the existing formula is nothing more than a bandaid.

Lol...I dont think people reccommend a bigger engine just coz of lag.
Getting a bigger engine just to reduce turbo lag is stupid. It costs more money, time and effort.

Easiest way is to decide what power goals you need and choose a suitable turbo for your needs. If that cant happen, change the turbine housing tio play with the A/R ratio.

Cheers,
Roy

 

[GrimJack]

A few comments.

Lag is not how long it takes to build boost from idle. From Google: "Within a turbocharger's operating range, lag is the delay between the instant a car's accelerator is depressed and the time the turbocharged engine develops a large fraction of the power available at that point in the engine's power curve."

Putting on twins can help, however, this is not a trivial task, and anyone who thinks they will get better response by throwing on a pair of turbos without building a sequential setup might as well wish for a unicorn, too.

There are several technologies being developed that should trickle down into the aftermarket turbo market soonish that will deal with lag, among them are foil bearings (http://en.wikipedia.org/wiki/Foil_bearing) and variable geometry turbos. (http://en.wikipedia.org/wiki/Variable_geometry_turbocharger)

Furthermore, many race cars have used an anti-lag system. (http://en.wikipedia.org/wiki/Anti-Lag_System)

 

[Poodles]

the Acura RDX has a turbo that has a flapper that switched between two different AR's on the exhaust housing

can't find pics of it, but the technology is stupidly simple, durable, and affective at making the powerband larger...