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Efficient boost level for PTE 6776 BB

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Dan SS2471

Active Member
Joined
Dec 12, 2008
Messages
218
In March I installed a PTE 6776 BB 'S' cover. Also replaced the stock IC with their SLIC.

Right now I'm running a TT chip / 93 octane. Base timing and I have about 10% fuel removed in all gears. It's still running rich - high 700s / low 800s on the O2s. No knock issues to speak of.

I've got the turbo set at 18 lbs.

I've made some baseline passes before adding Alky and upping boost and playing with timing (and fuel to lean it out a bit more).

Best pass so far is an 11.91 @ 109 with a 1.67 60'.

My first question is, does that ET look about right based on my setup and boost level? Second question is, once alky is added and timing and fuel are tweaked, would 24 - 25 lbs of boost get me in the high 10s?

Here are all of the supporting mods:

Engine/Exhaust:
-rebuilt about 5k miles ago
-204/214 flat tappet cam
-ported stock heads - Brosnonian stage 3
-steel center main caps
-double roller timing set
-60# mototron injectors
-TurboTweak chip
-160* t-stat with billet neck
-Caspers cam sensor cap
-3" ATR downpipe
-Turbonetics Evolution wastegate with in-car adjustability
-test pipe with cutout
-Hooker 2.5" catback
.020 forged JE pistons
-hot wired Walbro 340
-3" LT1 MAF w/translator
-Precision 6776 BB 'S' cover
-Precision SLIC

Sorry if I missed any key info. Appreciate any feedback.

Dan
 
high 700's low 800's isn't lean. You really need a wideband to know for sure. With 93 octane you would want to be in the 800's. With good gas I like to see high 700's even 80x's.
 
Yes, your et does reflect the mph for the state of tune. I've run 12.00's @ 109 - 110 myself, and with a 60ft that good, 11.90's is good.
That combination, with more boost, alky and higher timing should get your into the 10's with 24-27psi of boost. Keep concentrating on your 60fts, once you turn it up. And definitely keep an eye on your O2s and knock retard at higher boost levels though. That's very important. A powerlogger with wide band would be very beneficial as well. The older cast 6776 turbo, has a usable range of 17-29psi. Past 29psi, the charge temps start to get high. But with 25-26psi WOT, timing on 24-26* and alky, with a good 60ft, your combo should hit 10's.
Just my O2's worth.

Patrick
 
Thanks, guys. Forgot to mention it's also got a built trans from Michael's here in NJ along with a Protorque 3200 L/U.

Once the Alky kit is installed I'll start turning up the boost in small / safe increments. I'm not keen on completely relying on and tuning with Scanmaster either so I'll be borrowing a local's powerlogger once I start turning things up. I'll pick one up further down the line as well.

Patrick...you were very helpful when I first got the turbo back in March. If you recall, I had to return it to swap from an 'H' to an 'S' cover. Just wanted to thank you again for your help and getting it turned around quckly.

Dan
 
The 67 compressor will easily move mid 9 sec air before it runs out of breath. The hot side will cause a restriction before the compressor can even get close to maximization. John Crawford has run 9's on a 6776 3 bolt turbo.
 
The 67 compressor will easily move mid 9 sec air before it runs out of breath. The hot side will cause a restriction before the compressor can even get close to maximization. John Crawford has run 9's on a 6776 3 bolt turbo.

Good to know. My goal is to have a proven 10 second car that's reliable. It's mostly street driven and will see the track only a few times a year. It's going to be tricky once I go below 11.5x because I don't plan to cage it at this point. I say tricky because I have no delusions about adding alky, turning up the boost and clicking off a 10.xx pass. I want to get to that point safely without breaking anything and just know that's what it's capable of. But here at E-town they're pretty strict and it's going to take some passes to get it tuned and at the right boost level and I know they'll boot me and keep a record of it. Might have to look for a track rental or find a good dyno shop.

Anywho...thanks again for the info. Sorry for the tangent.

Dan
 
How are you guys "turning up boost" to 25-27lbs on composite head gaskets?
Would the steel shim HG be mandatory after say 21lbs?
Mike
 
How are you guys "turning up boost" to 25-27lbs on composite head gaskets?
Would the steel shim HG be mandatory after say 21lbs?
Mike

I'm not at those boost levels yet but Cometics and ARP bolts were used when the previous owner put the heads back on at rebuild time.
 
With a 70 turbonectis single BB at 22psi i went 10.93 at 123mph and a 1.51 short sixty, stock timing with a TT chip and alky, 02's were very lean around 750 you want to keep them around 780/790 range, the 6776 is a far more efficient with same boost and a little timing you should be able to get a 10.8 out of it if you get the car to hook in the 1.5 range.. :)
 
With a 70 turbonectis single BB at 22psi i went 10.93 at 123mph and a 1.51 short sixty, stock timing with a TT chip and alky, 02's were very lean around 750 you want to keep them around 780/790 range, the 6776 is a far more efficient with same boost and a little timing you should be able to get a 10.8 out of it if you get the car to hook in the 1.5 range.. :)

Thanks. That's a big 'if'. I doubt I'll see anything better than a 1.6 60' with my setup. But encouraging nonetheless. :)

Dan
 
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