Turbo swap woes

[CPRsm]

Need load on engine to make boost. No load in first, little in second.
I only see 9 psi in first with 3.31's and a heavier car than you. But 22 in 4th. Bummer about a stick. Especially if you don't have a boost controller. It will slow you down a tad.

Did Comp say they found anything wrong with the turbo when you sent it in? It does seem maybe you missed a bit on the clean up.

 

[JeremyH]

Comp said there was abnormal bearing wear iirc so they replaced the bearings.

Thats why I love the taller first gear with the 6060 vice the 3650 I can hit 16psi in 1st gear now

 

[dsmith658]

It was a torn up thrust bearing from what they told me.... And yes I think you're right that I missed something in clean-up. Not my first fuck-up :-/

Gears and boost controller is on my wish list for next mods.

Need load on engine to make boost. No load in first, little in second.
I only see 9 psi in first with 3.31's and a heavier car than you. But 22 in 4th. Bummer about a stick. Especially if you don't have a boost controller. It will slow you down a tad.

Did Comp say they found anything wrong with the turbo when you sent it in? It does seem maybe you missed a bit on the clean up.

 

[Bobby]

i was refering to the exhaust size on the turbo. is it a .81, or.96 or what.

 

[JeremyH]

The wastegate signal is in the compressor housing

You may have a small leak still. Easy way to check this is to temporarily move the wastegate source to he manifold and plug the compressor housing. And do the same boost test. This will allow the turbo to slightly compensate for the small leak and still reach full boost and will help you pinpoint the problem.

Also as soon as you can change out those stock chambered mufflers for a blow through style muffler do so. It will help reduce back pressure.

 

[dsmith658]

It's a .96

i was refering to the exhaust size on the turbo. is it a .81, or.96 or what.

 

[JeremyH]

It's a .96

I would have gone .68 on that turbo for your goals.


On my 6765 (same turbine wheel size as you) I made 650rwhp on a .68 housing no issue.

 

[Bobby]

that has a lot to do with how long it takes to spool it up. the 4:10's and that big of and exhaust side dont do well together, as far as spool up

 

[retfr8flyr]

Just out of curiosity what made you go with the .96 housing? That's a lot to spool with a 4.6. This housing and 4.10 gears I think are why you are not seeing the boost you expect. With your combination you aren't loading the turbo enough to make it fully spool in the lower gears. I would bet you wont see your full psi until top of 3rd or 4th gear.


Earl

 

[dsmith658]

I asked for a recommendation from the vendor, told him my wants (fast spool) and he told me to get this size to accomplish this goal. From what you're saying it sounds like I got a bad recommendation.

I'm doing a gear swap this week, it's just too much.

Just out of curiosity what made you go with the .96 housing? That's a lot to spool with a 4.6. This housing and 4.10 gears I think are why you are not seeing the boost you expect. With your combination you aren't loading the turbo enough to make it fully spool in the lower gears. I would bet you wont see your full psi until top of 3rd or 4th gear.


Earl

 

[retfr8flyr]

What gear are you going to install? Yes, I don't think you received very good advice but I could be wrong. I think the .68 housing would have been a much better choice with your stated goals. I was running 3.73 gears with a 28 inch tall tire and decided to try the 3.27 gear. I ran almost the same times, 11.78, with the 3.27 gear and 10# of boost but mile per hour was higher with the 3.27 and the car leaves soft, so I don't have to worry about track prep, if I want to turn up the boost.. The car is much easier to drive on the street with the 3.27 gears.


Earl

 

[CPRsm]

It was a torn up thrust bearing from what they told me.... And yes I think you're right that I missed something in clean-up. Not my first fuck-up :-/

Gears and boost controller is on my wish list for next mods.

Shit happens. No big deal. Something was found then. If you take the wastegate reference off, be careful. It will spool VERY fast. Do not wait to see boost. Anticipate it and let off as soon as you think you see one psi. With nothing cracking the wastegate at 2-3 psi, it is going up fast.

 

[dsmith658]

What's the purpose of testing with the wastegate reference line off? What should I learn?

Shit happens. No big deal. Something was found then. If you take the wastegate reference off, be careful. It will spool VERY fast. Do not wait to see boost. Anticipate it and let off as soon as you think you see one psi. With nothing cracking the wastegate at 2-3 psi, it is going up fast.

 

[AbdullaGT500]

I had 4.10's and a 67mm borg warner turbo with a .96 exhaust and I saw very little, if any boost in 1st gear. 2nd gear NEVER saw full boost.

 

[Bobby]

the 4:10 and a .96 is the reason

 

[JeremyH]

What's the purpose of testing with the wastegate reference line off? What should I learn?

Not off completely, move the reference source to the manifold like you would hook up a boost gauge. You have to also plug the fitting on the compressor cover. Now the wastgate will only fully open when the manifold sees desired boost so the turbo will over come any small leak int he coldside piping. If you get more boost then you saw before then you know you still have a small coldside leak.

 

[jodadejss06gt]

I have the .96 ar exhaust housing with 3:55's and I have 28" tires. I see full boost in 2nd and I can't determine how much I see in first as I spin. I'll have to try to get the go pro on my boost gauge during my next track event to see.

 

[rford426]

That's what I've been doing with my go pro using it to record my gauges at WOT

 

[dsmith658]

My old MasterPower was a .96 AR and I had full boost in 2nd prior to my swap to the Comp turbo. The main difference being the 62mm versus 70mm. Does this make sense or should I be looking harder for boost leaks?

I have the .96 ar exhaust housing with 3:55's and I have 28" tires. I see full boost in 2nd and I can't determine how much I see in first as I spin. I'll have to try to get the go pro on my boost gauge during my next track event to see.

 

[jodadejss06gt]

Well Dave I'd make sure all clamps were tight and visually inspect couplers also. One thing that does give clue is your making boost in 3rd and 4th. I'm not sure how much you should expect, but i'm guessing 1.5psi loss through your ic isn't too bad. I'm not expert but to me that tells me you aren't loading it enough. I'd say not even worry about the exhaust housing, but worry about the gears first. Once you get them on you can make a better assessment of whats going on.

My setup has I'm assuming the same wastegate spring that you are using and my wastegate signal is coming from the top of the intercooler. I don't know why but I see about 9lb on a cool day easily. When it was being tuned it even spiked to 9.5. My boost gauge is coming off the manifold too. My car is in the shop so I can't see how much boost I make in second, but I do know my car will blow the tires away so its hard to tell.