Wondering if there are people out there who have modified 20g turbos like many of us have on the 18g setups?

I have been searching on a number of forums and other reference sites and many have done the modified billet wheel conversions and machining to pickup significant gains in the 18g world. But I have yet to really find anyone doing this on the 20g setups with results. Lots of people saying that the power is not as responsive as that of the 18g turbos, which by the nature of size makes sense, but the top end gains have been greater.

Having picked up almost a 100whp with modified 18g's, i'm pulling my motor out to refresh bearings and valve seats, etc... and am thinking of going the route of swapping out my 18's to 20's and doing a similar setup. I am willing to sacrifice 3-400rpms worth of lag time, but I keep coming up empty handed with anyone who has gone the extra mile and had significant gains with a modified 20g setup. I've found a couple, but no-one posting up any sort of base numbers on a stock 20g v.s a modified 20g setup.

Any help on this guys would be very much appreciated as i'm looking to swap the whole setup within the next 3-5 weeks.

 

Ill be curious to see what your results are..was going to go this route when i had my motor out a month ago..but it would have meant bigger injectors, fuel pump EMS and tuning..I just decided i would rather have 5-600 hp that will last several years over 600+ that may/may not last...let me know how it works for you

 

The problem is the turbine side of the turbo. You cant get a big enough turbine in that turbo without changing the backside(means flange will change) or something else radical in which at that point you might as well build new manifolds and do a different turbo.

Generally anything over 25psi of boost creates way too much back pressure on the td06 or modified td05 housings.

 

How significant of a difference is there between the td05 and td06 housings?

Would the same amount of air be able to be moved on a 20g in reference to a compressor map at less psi? I can't find accurate comparisons for both.

Will the 20's bolt right up to my 18g manifolds? Haven't searched this one yet... Trying to weigh all options with the predisposition that if the motor is out of the car, any changes I want to make should be done at the same time.

I've stretched my limits for the 18's and know that, but as all greed goes, now I want more.

 

I just had my 18g rebuilt and I considered doing the 20g swap, what stopped me was the combination of the additional lag time, the benefits would only be on the very top end of the RPM range, the overall volume of airflow…I want to say the 18g were rated at 600 cfm and the 20g were rated at 650 cfm and when you factor in the sweetspot/efficiency range of each it just wasnt worth the swap.

 

The td06 has several variations which are all larger then the td05 and would are better suited to high boost on a vq35 then the td05

Doesnt matter how much air the compressor moves if it cant get back out through the turbine.

They do bolt up as long as its the 3-bolt flange pattern