Average repaint cost?

[6gunn]

Grumpy used a 6776 with a gated DP and controlled the boost. Think he used a Grainger valve.

Hmmm, maybe the wastegate hole needs to be opened up a bit? The downpipe is an RJC 3" so it has the large puck already. It would be great if there was a way to this turbo work, just lower the boost to a reasonable amount.

 

[SCOOBY DOO]

Hmmm, maybe the wastegate hole needs to be opened up a bit? The downpipe is an RJC 3" so it has the large puck already. It would be great if there was a way to this turbo work, just lower the boost to a reasonable amount.

I ran Jasons biggie puck with his DP to control my 6262 and opened up the wastegate hole. Not sure if the puck you have is the same size as his biggie puck he sells. Phone him and ask. His original puck in mine was smaller. Or unbolt the DP and take a measurement of the one in yours.

 

[Chuck Leeper]

As for lowering the boost level. I could only get it as low as 25psi...and that's with 0 preload on the wastegate arm. Boost came in very very slowly.

Another symptom of high back pressure.
Are you running a full exh?

 

[Pronto]

The chip was burned for a stock cam and heads.

Grumpy used a 6776 with a gated DP and controlled the boost. Think he used a Grainger valve.

Yes he did, but the engine was thoroughly optimized to support that turbo. IMHO, this engine is a mystery to longbed. This a prime example of not matching the turbo to the engine. There could be several issues going on at once. The first step should be finding a smaller turbo to see if the boost can be controlled. Once it can be kept to say 10psi, the rest of the issues this engine can be diagnosed.

 

[Pronto]

I bet with fresh set of valve springs and small billet turbo with a matching chip would rock.

 

[6gunn]

Another symptom of high back pressure.
Are you running a full exh?

Yes. Looks like 2.5" all the way to the tailpipes.

I bet with fresh set of valve springs and small billet turbo with a matching chip would rock.

I have a set of valve springs from Kirban. Planned to put them on the '86, but sounds like they need to go on this one now. I'd like to make this turbo work if possible. Not really wanting to spend 1K on a turbo right now. How close should I port the wastegate hole to the diameter of the wastegate puck? Should it be 1/8 smaller or is that too little? Is it more likely to crack if the wastegate hole is too close to the diameter of the wastegate puck? Pretty sure it's the "biggie" puck, but I'll have to measure it to know for sure.

 

[1KWIKSIX]

Yes. Looks like 2.5" all the way to the tailpipes.

I wouldn’t open up the hole more than 0.950”, be sure to radius the inner edges of the hole to smoothen air flow.
You can always go larger (no more then 1.10”) but you may have issues building boost if you go too large a hole at first

I have a set of valve springs from Kirban. Planned to put them on the '86, but sounds like they need to go on this one now. I'd like to make this turbo work if possible. Not really wanting to spend 1K on a turbo right now. How close should I port the wastegate hole to the diameter of the wastegate puck? Should it be 1/8 smaller or is that too little? Is it more likely to crack if the wastegate hole is too close to the diameter of the wastegate puck? Pretty sure it's the "biggie" puck, but I'll have to measure it to know for sure.

 

[SCOOBY DOO]

Porting the wastegate hole isn't an exact science. Go to big, and you'll have a problem making decent boost pressure. I'd go .900 and work from there. If you can get the boost down it may give a clue as to what's going on. Not knowing the engine you have isn't helping. Not your fault tho.

 

[SCOOBY DOO]

Weak valve springs USUALLY rear their ugly head in high gear.

 

[Pronto]

And higher rpms. If that cam is in fact stock, there is no point in going to 5200+ rpm.

 

[6gunn]

Ok, I'll throw these Kirban springs on there. Also have a gram scale on the way so I can get the governor sorted out. Also going to port the wastegate hole and see if the boost lowers closer to 20psi. Sound like a good plan? Shooting for very near 5,000 RPM on the 1-2 WOT shift. Does that sound ok or do you think it should be lower?

 

[Pronto]

Did the governor throw the spring? Is that why you put that nylon screw in? Have the weights been ground on?

 

[Jerryl]

I realize there are opinions on the use of a dyno, but this tool (dyno) combined with expert knowledge, will help with determination and optimization.

 

[jay dcpt]

Why would you put on a set of "kirban" springs without knowing what cam is in it. Are you sure it's stock?

 

[6gunn]

Did the governor throw the spring? Is that why you put that nylon screw in? Have the weights been ground on?

Yep, the governor spring was in the pan and I used the nylon screw to pin it. The weights haven't been touched except for the hole I had to drill in the small weight for the screw. It had an indentation, but no hole.

I realize there are opinions on the use of a dyno, but this tool (dyno) combined with expert knowledge, will help with determination and optimization.

I would LOVE to get this car on a dyno to help solve this problem along with a bunch of Buick guys to look it over. I know some, but would yield to the experts in a heartbeat. Any dyno days in the Texas panhandle?

Why would you put on a set of "kirban" springs without knowing what cam is in it. Are you sure it's stock?

Out of ideas and new springs are just one less variable to deal with. Though, I'm starting to rethink this. It pulls well all the way up to 5,800 which is higher than I want to rev anyway. Revs just fine to 5K, so I think it might be better to hold off on the springs until I can bring the shift points down.

 

[Pronto]

You could pull a spring or 2 and test it on one of those testers you use in a vise. Right now by buddy is breaking in his refresh with some old stock springs that were around 70. They will be coming out in 200 more miles. Then the fun begins.
Think you're on the right track overall. Too bad the po got sold that turbo.

 

[Ttype6]

Do you think the valve springs are so weak that they aren't able to close under so much boost(30ish)? Would it be worth a shot to turn the boost down to 25 or 20 and make a WOT pull to see if this confirms the problem being weak springs?

.While boost pressure and exhaust back pressure need to be considered when selecting valve springs,the major factor is rpm. The first thing to do is to get the trans to shift at a lower rpm 5,500-5,600.

 

[Ttype6]

If it were valve springs, wouldn't the motor come back after the RPMs drop to a certain amount?

Yes,if the problem was weak valve springs. If you have weak valve springs for the rpm your cam wants to run at,you will notice the power fall of dramatically with an accompanying fluttering sound. Then,when you shift into the next gear while remaining at full throttle,the power will come back instantly and fully.

 

[Ttype6]

What chip are you running? It almost looks like it has a rev limiter on it. It looks like the fuel is being shut off at around 5900 rpm even though the injector duty cycle is still up so maybe spark is being shut down?

If the fuel was being shut down by the chip to control revs,the duty cycle would drop and the fuel would be immediately be re-applied after the revs dropped restoring the engine to full power while the gas pedal was constantly to the floor.

 

[Ttype6]

If it really a stock cam and heads it would like to shift around 5000- 5200 max maybe a little sooner.

It would also never rev or make power to 5,800 rpm.