Anyone else running Precision 5857?

[1KWIKSIX]

Recently installed my new Precision DBB 5857 (.63 A/R) with S ported shroud. I've got a 3" internally gated DP.
My initial set up was with an adjustable HD wastegate actuator & RJC Boost Controller / Bleeder Valve.
Waste gate rod had 1/8" tension & RJC Valve fully open.

Because I've still got my stock D5 installed, wanted to try the RJC boost controler / bleeder valve to help spooling (cause I heard it could be a bit lazy with a D5).....I do have a PTC 10" L/UP 2800 to install once I get the boosting issue under control.

I ran into overboosting problems and had to take my foot off the gas at around 23-24 lbs boost (and rising fast).

Boy these turbos spool quickly.

Since I am not spraying alky....just 94 octane pump gas.....I decided to change over to the standard actuator.

Same results with overboosting. Maybe it's just a spike, but I've had to back off immediately once I see the needle race past 22lbs boost.

I have not matched the WG hole to the puck or ported / radiused the inside edge yet. Didn't think that it would be a problem on such a small turbo.

I'm going to be removing the RJC Boost Controller Valve and try a run using the factory's stock electronic waste gate control valve instead. Not sure if this will make a difference or not.

Just for the record.....have been running 20 lbs boost with no knock on my set up for years, even gone as high as 22lbs boost for a period of time with no KR.

If anyone can comment on their experiences with this turbo and boost issues...please chime in.

Patrick.....are you out there?

thanks,

dave

 

[turbo nasty]

I had teh same problem on my GT3255E ..I would try porting it. leave at least .050 around the edge of the hole to puck to seal tho

 

[NicksTurbo6]

Subscribing. I just ordered the same exact turbo from Patrick on Thursday. My set up is VERY similar to yours.



Nick

 

[forcefed3.8's]

Try it without the RJC vavle. The valve has a bleed hole in it, which raises the boost without any tension on the check ball.

 

[3.8L V-8 eater]

Try it without the RJC vavle. The valve has a bleed hole in it, which raises the boost without any tension on the check ball.

This helped my boost spike issue by taking off the manual b. controller...Now that the puck is ported and things seem normal going to put on RJC controller and cautiously check things out!!

 

[trick86]

I found I had a very similar boost spike problem when I went from a stock turbo to a TA-49. Backed my actuator right off to the point it had little to no tension and still wicked boost spike...and we talking 25psi+ like right freaking now, had to lift. Porting and blending the waste gate hole to 1.100" was the only proper fix, spent lots of time on the blend keeping air going through the turbo or easily exit the gate when the puck opens. Hope this helps out.

 

[hensleyt]

I run a E-boost street no porting, small boost spike 19-20 then it comes down to 17 very fast but no KR ,thought about porting it ,just have not done it.Its a bit $$ but I like the way it works on the street and on the track,its on the money at the track. I use the standard actuator.It took about 5 trips up the road to get it right, Its very stealthy.

 

[SCOOBY DOO]

All you have to do is port it...don't know what the big deal is.

 

[hensleyt]

Why is the port too small in the first place?post after post we see boost spike.I just orded my Eboost at the same time I orded the turbo

 

[turbo nasty]

Are you in denial?? Lots of great advice and guidance......Many users of PTE stuff on this board......Port the hole. Those housing are cast and more than just buicks run thme. For our application they frequently need porting for boost control

 

[threerail]

every ones said it, port the hole to about 1 inch and blend it in to the housing, u can do it on the car if you like, the chips will just blow out the exhaust, the boost is overwhelming the ability of the hole to dissapate excess boost quickly. this causes the spike, if u r not convinced, disconnect the wastegate and try it like that, you will see the spike without any wastegate function, because the hole wont flow enough to keep ahead of the turbos push, see what i mean? good luck we all been there, rob