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Supraddict
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Discussion Starter #1
I know these are probably newb questions around these parts, this is the first time I've posted in this section, but I just have a few :sadance:

I know that people who auto-x and/or road race their MKIV's prefer smaller to medium size single turbos such as 61, 63, and 67mm turbos, the latter being quite possibly the best "happy medium" turbo for the MKIV these days. For one, they offer the needed quick spool for track situations, and secondly you don't really need more than 500-550hp in any of these situations.

However, how/why is it that most tuners in Japan run huge single turbos, most often ones like the T88 and 88H? The Jun 200MPH Supra is an example, as well as the slew of Signal Auto, Nagisa Auto, and Auto Select R34 Skylines, all running big single turbos. How do they make it work? The associated lag and 800+HP on the track? Why don't we do the same? I know the AWD Skylines are undoubtedly more successful when it comes to putting the power down, but it seems like large single turbos are preferred.

Lastly, does anyone road race an MKIV with HKS twins? Something I've often wondered...yes they are expensive, heavy, complex, and generate a lot of heat, but they easily make enough power for the track and have a smooth, linear powerband. Seems like they would work?

Thanks for your answers!
 

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rcsupra said:
.....

I know that people who auto-x and/or road race their MKIV's prefer smaller to medium size single turbos such as 61, 63, and 67mm turbos, the latter being quite possibly the best "happy medium" turbo for the MKIV these days. For one, they offer the needed quick spool for track situations, and secondly you don't really need more than 500-550hp in any of these situations.

Agreed. In fact, I run a 57mm!

However, how/why is it that most tuners in Japan run huge single turbos, most often ones like the T88 and 88H? The Jun 200MPH Supra is an example, as well as the slew of Signal Auto, Nagisa Auto, and Auto Select R34 Skylines, all running big single turbos. How do they make it work? The associated lag and 800+HP on the track? Why don't we do the same?.......!
Are these "tuners" road racing? (I don't know). Typical road racing doesn't get near 200 mph for a car like this. Lag would be a big problem on a regular road course with the big turbo.
 

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Supraddict
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Discussion Starter #3
Yes, the aformentioned cars are all road racing track cars, often built for time attack situations on tracks like Tsukuba and Fuji Speedway. Perhaps they use the big singles for the straight sections, and just deal with the lag in the corners, I don't know?
 

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I wonder if they implement "anti-lag" techniques, which would to a large extent alleviate lag issues with big turbos ...at the expense of turbo life and other problems that you can live with on a race car being rebuilt after ever race but would not want to live with in a street car. For example, blowing raw fuel into the exhaust mani or turbo inlet to spool it is very tough on hardware but it will spool the turbo.

I suppose if you are building a dedicated hardcore roadcourse Supra, you can do things I would never even consider.
 

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True usually about 40% of the time attack cars have problems during the events.
You are also seeing professional drivers with eons of experiance driving those monster cars. For the average street driver to try and drive one of those cars at the limit on the track is kind of like tow in surfing 60 ft waves as a beginner.
 
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