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SR20DET TD06-18G sort of slow to spool

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Hello all. I just recently dyno tuned a friend of mine's sr20det setup is below.

Sr20det black top

Kinugawa td06-18g

Log style top mount


850cc injectors

Hallman boost controller

Apexi power fc djetro

The car runs extremely well made 362whp and 332ft lbs at around 5300 rpm

The issue is the turbo doesnt reach peak boost of 1.3 bar until around 4200rpm. My previous experience led me to believe that a smaller turbo such as this one should be making full boost alot sooner, I would assume around the 3k -3400rpm range.

There is alot I will check again. Along the lines of gasket failures, manifold cracks, so on and so forth. Is there anything I should be looking at on the timing map? Just trying to cover all my footsteps. Thanks in advance

It`s not a small turbocharger for 2.0L engine, everything is as expected. I think that TD05-20G should fit better for your requirements, but I doubt that you can reach full boost on 3400 RPM even on that turbocharger. If you don`t want to change the turbocharger, you could fit a twin scroll housing on it and a well done twin scroll manifold, it should drop the spool treshold at around 200-300 RPM or/and choose the turbo housing with less A/R

I've used various TD06's on 4G63's and I wouldn't say they are in the least bit responsive. A key part that you haven't mentioned is the AR of the exhaust housing as a tight housing will tend to provide more exhaust energy to the turbine wheel and improve spool (at the expense of high rpm back pressure).

The TD06 turbine wheel is a pretty ancient thing by the standards of some of the modern turbochargers we have access to and hence the results you're likely to see are only relative to this.

On the subaru impreza platform the 18g or 20g are still very common. What I'm know also alot aftermarket turbos like Blouch are based on them. But thats maybe only because there are no plug an play turbos like EFR available for subaru...

Lamar, you can easely improve the setup. I'm really not a fan of the log style manifold. Have a look at this link.


Concurring with what others have said, that sounds relatively on-point for what I'd expect from a TD06 18G.... I doubt you're going to find something which will result in much of an improvement.

Yep, I did a TD06-20G on a RB25 today, wasn't seeing peak boost til 3900 on the 2.5.

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