S13 Questions

[TLoke13]

Just like the title says, have a couple questions about my S13 with a S14 SR20 I just picked up.

1). Built SR20 with Greddy intake and stock throttle body. Also running a Tomei M8270 turbo. What size throttle body should I upgrade to? 80mm?

2). Have yet to get the car on a lift but wanting to get ideas or possibilities before I do. Drove the car for about 2hrs with zero problems. Today got it warm, shifted into 4th around 50mph, and a violent shake felt like the rear end was bouncing off the freakin road....like I said, haven't gotten under the car yet. Then immediately slowed and turned around then got back to 50mph and no shakes, hit 60mph then went to slow down off throttle around 48/50mph the violent shake hit for about 5secs.....any ideas? Thank you

[DennisC]

1. The largest oem throttle body you can bolt onto the s14 sr is the s13 sr throttle body. I have seen aftermarket 70mm bolt on throttle bodies you can get as well. Anything larger will require an adapter or modification the flange on the intake manifold.
2. Check rear subframe bushings to see if they are ripped or torn

[angel mkiv]

80mm throttle body's are usually over kill for bottom mount turbos,get a n15 pulsar 70mm throttle body for a upgrade..as for the clunking issue first raise it and check for anything obious.you never know what the previous owner installed or done to it..but usually it's the rear subframe bushings like mentioned above me.

[Atill93]

i had a similar vibration issue in my s13 when i first got it. around 30-35 miles per hour the rear end felt like it was vibrating and shaking like crazy. my car hasnt been on the road in 8 months but i put a new differential, new rear axles and rear subframe bushings so i hope that fixes it