Slow Boost? b16 57trim
 

I put together my turbo setup a few years back and it always seemed pretty laggy. I got a precition sc34 57trim compressor with a 63ar turbine i believe I dont get full boost (7psi) until around 5500 rpm in 2nd gear. Does this sound right with your experience? The turbo is oil seal is starting to go so im thinking of getting something smaller such as a 50trim t3/t4e 63ar on the exahust. Will that spool alot faster or be about the same. I live around 6000ft so that my explain my slow boost. edit its a b16a first gen stock internals. Ohh what happened to this site it seems way different from when I was on here around 2003 or so with my old name b16civc or something like that...

If I were you I would go with a smaller t3 ar .42 and .48 A good friend had the ebay t3 on his LS eg hatch and he said it pulled ALOT better than the t3 t4 both @ 7psi. he said the t3 t4 took some time to spool while the t3 was fast to spool up. he walked a bolt on trans am from a roll with the smaller t3.

The .42 a/r compressor is T3 and much too small for a good B-series build. Then again, if he's only looking for 7psi then it would be fine. For a low pressure set-up a small turbo isn't a bad idea at all and cheaper too. It's just a bit small for high rpm use and that's what B-series are good for. The largest compressor you can get in the .42 housing is a 50 trim T3 IIRC, and that's less than 45mm. A 50 trim T4 is usually in the 54-58mm range so much larger. 7psi by 5500 rpm is terrible. A GT42 would probably build that much boost by 5500rpm lol. I'd say there are other issues than just a laggy turbo because a T3/T4 uses the T3 turbine wheel still and should build boost much faster than that.

[QUOTE=crxb18t;1262465]If I were you I would go with a smaller t3 ar .42 and .48 A good friend had the ebay t3 on his LS eg hatch QUOTE]

I know what the .42 is. like I said the t3 will be your best bet. I bet it will spool up fast and hold well. just try it you can get them all day long and they dont cost much.

Yea the T4 is WAY too big for that b16. I just sold my T4 off my h22 and they are huge compared to the t3 t4 even.

[QUOTE=crxb18t;1262493]Well not a full T4 turbo. Just the compressor side T4. Still retain the T3 turbine components hence the T3/T4. No doubt a full T4 would be way laggy as even the smallest T4 turbine is too big for a small displacement/low boost set-up. I've seen B-series running full T4's make insane power though but of course only at high rpm and high boost. I agree that a full T3 would be a good choice if his goals are only 7psi. I would personally go with the larger 60 trim T3 compressor like off the t-birds as the .42 is pretty small for a B-series even a low pressure set-up IMO.

Yea I dunno how the full t3 was at high rpms cause I didnt ride in his car after he changed out the t3 t4 to the t3 he just said it pulled way better and spooled up fast, but I do know that the to4e lagged pretty bad on my b16. Im sure the T4 on my built h22a would have made some nice numbers

I have a pretty good street tune. I have it run slightly rich 13.5 at WOT until boost then it drops around 12.3 or so. the crusing part of the map seems to be pretty solid. I just did some preliminary troubleshooting and I think i might have some pin hole leaks somewhere in the charge piping or intercooler. depending on where I hook up the wastegate I get a 3.5 psi change in total boost.

For example, If i have the wastegate connected to the compressor I only boost around 3 psi and if I connect it to the intake manifold I boost around 6 ish to 7....

I want to get this sorted out before I try to up the boost anymore but The AFR's are good and safe in boost. As soon as it warms up and stops snowing im going to decommission my car for a weekend and sort it out.

have you everseen such drastic losses from a few pinhole leaks. All my clamps are good and solid. Its hard to believe than more than a few CFM of air escaping through some possible shoddy welds. I think a b16a runs around 275cfm or something at 10 psi