10.99 on E85? Got a Couple Questions

[turbo89]

That's not true. Boost is measured at the TB and with an unopened engine, it takes a lot of pressure to get air past those tiny valves. Cylinder pressure is what's hard on HG's and 390whp is WELL within the limits of stock HG's. People get so hung up on the boost pressure when it really doesn't mean much at all.

So let me get this straight .. your saying 10 psi of boost exerts the same stress level on head bolts / gaskets as 30 psi does at the same power level ?

IF this is what your saying please explain to me why if I kill the cylinder pressure with a cam change but yet retain 30 psi of boost do I still lift cylinder heads ?

 

[BEATAV8]

Should I be worried? This one has never been apart.

 

[we4Mateo]

So let me get this straight .. your saying 10 psi of boost exerts the same stress level on head bolts / gaskets as 30 psi does at the same power level ?

IF this is what your saying please explain to me why if I kill the cylinder pressure with a cam change but yet retain 30 psi of boost do I still lift cylinder heads ?

Yes. 10psi on a stage II build will exert the same pressure on stock HGs as an unopened motor at 30psi. If you're lifting heads with a small turbo at 30, it ain't the 30psi doing it; it's a bad tune.

 

[we4Mateo]

So let me get this straight .. your saying 10 psi of boost exerts the same stress level on head bolts / gaskets as 30 psi does at the same power level ?

IF this is what your saying please explain to me why if I kill the cylinder pressure with a cam change but yet retain 30 psi of boost do I still lift cylinder heads ?

If the cam change nets more power, it's because you have increased cylinder pressure. Cylinder pressure may go down at idle and part throttle from a cam change, but only if you change a cam and make less power are you lowering stress on the motor, regardless of boost pressure.

Boost is a better measure of what your engine CAN'T eat. MPH through the traps or hp on a dyno are what determines HG needs; and even that is heavily debated as to what to run and when a change from stock is needed.

 

[turbo89]

Yes. 10psi on a stage II build will exert the same pressure on stock HGs as an unopened motor at 30psi. If you're lifting heads with a small turbo at 30, it ain't the 30psi doing it; it's a bad tune.

HUH .. a STAGE II build has 6 extra bolt holes / bolts and a typically a lot thicker deck head is used ... DUH it won't exert the same load on head gaskets or head bolts and since when is a TA 61 a small turbo ? That's what the guy has in his sig a bad tune has nothing to do with it .. the heads lifting isn't from detonation .. you can have ZERO knock ZERO detonation and lift heads ! ... the stock head gaskets / bolts won't live long running around on 30+psi

 

[turbo89]

If the cam change nets more power, it's because you have increased cylinder pressure. Cylinder pressure may go down at idle and part throttle from a cam change, but only if you change a cam and make less power are you lowering stress on the motor, regardless of boost pressure.

Boost is a better measure of what your engine CAN'T eat. MPH through the traps or hp on a dyno are what determines HG needs; and even that is heavily debated as to what to run and when a change from stock is needed.

yes we all know boost is what the engine can't process ... if you are seeing an increase in boost its air that isn't processed .. where is that air going and what is it doing ! as I posted above .. if I install a cam and totally kill cylinder pressure ( which is super easy to do) .. and LOWER POWER LEVEL as a result of the cam change ... if I maintain the SAME BOOST 30 PSI...
why am I still lifting the heads with NO DETONATION ... please explain

 

[turbo89]

Should I be worried? This one has never been apart.

Depends on how many times .. for how long you wanna do that .. if your gonna tell me you have 100's passes on that same setup on stock HG with a TA 61 turbo .. I'm callin bullshit .. anyone can datalogg a few passes @ 30 psi and tell the tale .. but don't make it out to be like you can run 30 psi as long as you want with stock like reliability .. that's a tale for kids bud

 

[we4Mateo]

@turbo89 Plenty of people have multiple 30psi street hits and 1/4 mile runs on stock HGs; including myself, so the proof is in the pudding as they say. And yes, a TA61 is a small turbo; it's the exhaust that is the cork. If the heads are lifting with an actually good tune, then tighten the bolts. The stock bolts will work fine still though; even just 8 of them.

 

[we4Mateo]

HUH .. a STAGE II build has 6 extra bolt holes / bolts and a typically a lot thicker deck head is used ... DUH it won't exert the same load on head gaskets or head bolts and since when is a TA 61 a small turbo ? That's what the guy has in his sig a bad tune has nothing to do with it .. the heads lifting isn't from detonation .. you can have ZERO knock ZERO detonation and lift heads ! ... the stock head gaskets / bolts won't live long running around on 30+psi

Bad example I guess using the stage II but cylinder pressure equals hp regardless of how you make it.

yes we all know boost is what the engine can't process ... if you are seeing an increase in boost its air that isn't processed .. where is that air going and what is it doing ! as I posted above .. if I install a cam and totally kill cylinder pressure ( which is super easy to do) .. and LOWER POWER LEVEL as a result of the cam change ... if I maintain the SAME BOOST 30 PSI...
why am I still lifting the heads with NO DETONATION ... please explain

I can tell you that the air isn't making it past the valves so how is it lifting the head? If anything, we should be blowing intakes off at 30+psi!

 

[turbo89]

Bad example I guess using the stage II but cylinder pressure equals hp regardless of how you make it.



I can tell you that the air isn't making it past the valves so how is it lifting the head? If anything, we should be blowing intakes off at 30+psi!

It isn't make it passed the valves .. really ???

So like champion irons that have marginally bigger valves than stock (.060 difference) still would hold the air back then because of the valve size ??? if that's the case whats the point of the port work ? we could all just install bigger valves and call it good ..

if the air isn't making it past the valve ..... how would you make more power without more air ??? please explain ...

 

[dvernst]

Depends on how many times .. for how long you wanna do that .. if your gonna tell me you have 100's passes on that same setup on stock HG with a TA 61 turbo .. I'm callin bullshit .. anyone can datalogg a few passes @ 30 psi and tell the tale .. but don't make it out to be like you can run 30 psi as long as you want with stock like reliability .. that's a tale for kids bud

This car has been running like this for years now, and is unopened with 265,000 miles

 

[turbo89]

This car has been running like this for years now, and is unopened with 265,000 miles

Are you saying its making almost 400 rwhp and has 100's of 30 psi 1/4 mile passes with 265K miles on the clock ?

Or are you saying it has a few 30 psi runs a year on a stock turbo for the last few years and the car is driven daily by the wife and now has 265K miles on It ?

 

[dvernst]

Are you saying its making almost 400 rwhp and has 100's of 30 psi 1/4 mile passes with 265K miles on the clock ?

Or are you saying it has a few 30 psi runs a year on a stock turbo for the last few years and the car is driven daily by the wife and now has 265K miles on It ?

It's not my car, so I shouldn't be speaking for him, but it has not had 100's of 30psi passes on it, but it has a bigger than stock turbo, and has been 30+ psi for a few years now. It goes to the track a few times a year...

 

[we4Mateo]

It isn't make it passed the valves .. really ???

So like champion irons that have marginally bigger valves than stock (.060 difference) still would hold the air back then because of the valve size ??? if that's the case whats the point of the port work ? we could all just install bigger valves and call it good ..

if the air isn't making it past the valve ..... how would you make more power without more air ??? please explain ...

Better heads flow more air equals more horsepower equals more cylinder pressure regardless of boost. What gets in the cylinder is what lifts the head which equals hp which equals mass flow and it still has nothing to do with boost as a number. Champ irons allow you to a) make the same hp on less boost bc the engine eats betters or b) make more power at the same boost level assuming you weren't maxing out the compressor before at the same boost level. And yes, even the champ irons are what hold back the motor and allow to make "boost" at all; as you agreed, boost is just what CAN'T be taken into the motor.

Either way, boost is still just a number and an unopened engine at 30psi is less stress on head bolts/studs and head gaskets than a champ ironed stroker at 20psi with a big turbo.

 

[we4Mateo]

Are you saying its making almost 400 rwhp and has 100's of 30 psi 1/4 mile passes with 265K miles on the clock ?

Or are you saying it has a few 30 psi runs a year on a stock turbo for the last few years and the car is driven daily by the wife and now has 265K miles on It ?

My car has 400rwhp on 25psi and it's NEVER below that. 70k miles under my ownership, 50k with TE44, 45k with alky at 20psi+. 150 recorded passes in the 11's at 115mph+. Opened once b/c I lifted the hewds when voltage dropped at 25psi and kablooyaca! I drove it another 2k miles after that. Took it apart when we swapped the cam and dropped the pan and saw stars. Machine dude straightened all 6 rods and I still run them with stock pistons and rings. Port matched heads and a small FT cam on otherwise stock rotating assembly. Heck, I haven't even had an oil cooler for the last 30k miles and 75 passes. I've gone 120mph on my TE44 numerous times in the 1/4 and plenty of OD 130mph highway runs in Mexico so I use "all the boost" as the southern boys say. I've never lifted a head except the day I let my tune slip and even then it resealed and got me home. If you can't run 30psi reliably with a TA61, you have homework to do, and stop blaming a meaningless number.

 

[delcowizzid]

cylinder pressure shouldnt exponentially go up with boost you should just get the same pressure for longer amount of time during the down stroke to gain the torque/power.

 

[we4Mateo]

One thing worth mentioning, and this does pertain to the OP using E85, lower boost is easier to get a cool intake charge regardless of type, if any, of pre-valve intake cooling. Running 30psi will heat the air more than 20psi, but race fuel, E85, alky injection, or a combination of them, will negate these effects thus making the cylinder pressure points noted still relevant.

 

[BEATAV8]

Depends on how many times .. for how long you wanna do that .. if your gonna tell me you have 100's passes on that same setup on stock HG with a TA 61 turbo .. I'm callin bullshit .. anyone can datalogg a few passes @ 30 psi and tell the tale .. but don't make it out to be like you can run 30 psi as long as you want with stock like reliability .. that's a tale for kids bud

Car has been running this way for better than 5 years. Ask anyone in the Chicagoland Buick Chapter or at the Turbo Farm. Benny, Paul Duboise, Pitts, Prasad, Joe Garcia, Lloyd B, Dave Vernst, Steve Else, JasJamz, they all know this car.

Most recent track outing was 2 weeks ago at Byron with the Buck club. She sees 30+ PSI every time she's driven, not just at the track.

another snippet from back in 2011:

 

[Sweet6]

I agree I have seen a lot of stock longblock take 30 or near 30lb passes for a long time My buddy bracket raced his car at 28 or higher for years until a head gasket let go At least a 100 passes like that and probably 500 plus passes on the engine

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[krom]

I know a car that made 300+ runs on a unopened motor with a 61 turbo that ran in the high tens. He ran high 20's to 30 lbs of boost on 116 in crappy Phoenix heat. The only people I would listen to are people who have accomplished what you are trying to achieve, E85 is different than race gas which is different than alky.