1990 DA B20 turbo.. need some small help... small build thread

ASSISTANCE Forced Induction
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Hi guys, long time lurker, first time posting. I have owned 5 DAs in my day, 3 b18 and 2 b20s. I have run across some extra money with taxes and decided to turbo my B20 swap. I have been around cars for a long time but have only one 1 turbo’d car, a mk4 GTI. I have a few questions that I have tried searching for and haven’t really got a clear answer on. So, sorry for the noob questions but I tried looking.

  1. I have a t3/t4 .57 trim .63ar exhaust mounted to a blox manifold. I am running into fitment issues. I read that some modding to the casting on the block is an option. The other option i saw was a half radiator from say a civic. I was wondering what has worked best for these turbo setups.
    hitting on casting.

    hitting on radiator.

  2. I have read and googled and asked many people but I still dont understand the oil lines INTO the turbo. My turbo has 2 of the openings just like the one shown. 1 on top and 1 on bottom. Feed and return. I got that part but, I have been told that the feed line and return line should not be the identical. I dont see how this works though. they should have the same flange right? Maybe some detailed pics of oil line setup would help.
    2 flanges just like this.

  3. How often do people run into the Tial wastegate being too tall to close the hood off a blox header?

Thanks for all your help in advance
1990 DA9
B20 swap
Brian Crower Cams
Comp Clutch
H&K Lowering Springs
Konig B-Bombs15X7
Toyo T1R tires
Front and rear lower sway bars
Chipped ECU with a Chrome basemap
OBD0-OBD1
450cc bluetop injectors
Godspeed Intercooler
Blox turbo Manifold
57 trim turbo with .63ar exhaust
Walbro 255 fuel pump
Greddy BOV
Thermal R&D 3inch exhaust
Tial 38mm Wastegate

she looks rough now, but you dont have to look good on the autocross course. :slight_smile:



Thanks for all your help and I will keep you posted on progress.

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1=get a half size radiator from a eg ,it will help with clearence for the turbo.
2=you should have to oil flanges that bolt up to eather side one should be -3 or-4 fitting for the feed,and the bottem should be a -10 for return.be sure to use gaskets.
3=as for the wastgate hitting the hood not much u can do there besides buy a shorter wg or a better mani but try to cut the ribbing out of the hood to gain some more space?..
glw the build ,and happy boosting!!..ps. check the turbo guid out in the thread its a sticky up top alot of good info there…

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  1. Option 1-You can clearance the block with a 6" grinder and grinding wheel or flapper wheel fairly quickly.
    Option 2- As said earlier, put a 92-00 Civic radiator in the car if you want to exit the downpipe on the passenger side.

2.Clock the center section as you have the return side actually on top. The 2 flanges are not the same. The return has the “square” center hole, the feed will have a smaller round or sometimes female threaded center hole.

  1. Remove the top air fitting if you are only running wastegate pressure to allow for a bit more clearance. Or you can use a 38mm wastegate elbow to lay the gate parallel instead of vertical.