posi rear

[jimski]

My hybrid olds carbed hotair setup has 2004r bq trans trango shift kit d4 converter 2.41 rear(peg leg).Installing a posi unit 3.42 will this give me more boost.The car gets recomended 9 lbs boost but i have to be in it and in overdrive on the highway. Running around town i get about 6 psi.Just wondering if the rear end is playing any factor in why i only get 6 psi around town.The quadrajet 's secondaries are opening as they should.I still have a stock olds exhaust,the waste gate is adjusted.I understand it could be a few things why i dont get 9 psi around town norrowing down Im thinking the rear is playing a big factor to why it dosnt get 9psi around town.

 

[usetaboost]

I wouldn't think that would have anything to do with it. I would check ALL vac lines. and cracked exhaust manifolds or leaks. report back

 

[jimski]

wouldnt the 3.42 rear put a more extensive load on the engine around town thou thus making more boost

 

[usetaboost]

putting the 3.42 gear in should make no difference. The 83 carb turbo cars had this rear, You must have a vac leak or a cracked exhaust manifold

 

[jimski]

putting the 3.42 gear in should make no difference. The 83 carb turbo cars had this rear, You must have a vac leak or a cracked exhaust manifold

Thanks for the reply. This is in a hybrid olds cutlass 2.41 rear currently. Everything is sealed up.

 

[Freddie's Buick]

.....I still have a stock olds exhaust.....

The back pressure may be differant running an N/A exhaust?
Is that the type of exhaust you have, or do you have the oem turbo type?

 

[dr_frankenstein]

I understand what your saying.

I do believe your correct on engine load being a factor in the amount of boost being produced...

When you said you had to be in overdrive and in it.... thats the point where the engine is working the hardest, thus cylinder pressure is the highest, and so boost follows. your ratio was more than 1 to 1 final drive, the engine is turning its slowest relative to your speed.

Around town its not working as hard and so boost is lower. compare the ratios 1-4 in the trans, you rarely hit OD around town, not a lot of work for a healthy engine.

changing to a 3.42 rear is only going to make the situation worst. engine load is the key element. thats why you cant build boost in park!

you need that adjustable rod on your wastegate actuator, or a bleeder on your actuator line. that will help out.

I see where this can be confusing, the factory "RATED" the cars at 9lbs of boost or soo, but has anybody actually documented this is what it makes in stock form? as there isnt a boost gauge factory....... i suspect the boost is actually much lower most of the time.

A.j.

 

[usetaboost]

my car made 9 lbs stock. It had a new turbo and yes it was a new wastegate with an adjustable gate. It took no tuning though. Slapped it on and hooked up the vac and was set at 9 lbs. There was something wrong with mine, pretty sure it was running way lean. I could never tell a difference between 6-9 lbs of boost. That sucker did run hard for what it was though.

 

[jimski]

The back pressure may be differant running an N/A exhaust?
Is that the type of exhaust you have, or do you have the oem turbo type?

n/A I know for sure this is one of my troubles 2 1/4 pipe

 

[jimski]

I understand what your saying.

I do believe your correct on engine load being a factor in the amount of boost being produced...

When you said you had to be in overdrive and in it.... thats the point where the engine is working the hardest, thus cylinder pressure is the highest, and so boost follows. your ratio was more than 1 to 1 final drive, the engine is turning its slowest relative to your speed.

Around town its not working as hard and so boost is lower. compare the ratios 1-4 in the trans, you rarely hit OD around town, not a lot of work for a healthy engine.

changing to a 3.42 rear is only going to make the situation worst. engine load is the key element. thats why you cant build boost in park!

you need that adjustable rod on your wastegate actuator, or a bleeder on your actuator line. that will help out.

I see where this can be confusing, the factory "RATED" the cars at 9lbs of boost or soo, but has anybody actually documented this is what it makes in stock form? as there isnt a boost gauge factory....... i suspect the boost is actually much lower most of the time.

A.j.

It is adjustable,and adjusted.Why would 3.42 make it worst wouldnt the engine work harder with that gear.My exhaust is 2 1/4 this has to be the at least one of the probs... I hollowed out the cat a while back but still has factory muffler.

 

[Freddie's Buick]

It is adjustable,and adjusted.Why would 3.42 make it worst wouldnt the engine work harder with that gear.My exhaust is 2 1/4 this has to be the at least one of the probs... I hollowed out the cat a while back but still has factory muffler.

The 3.42 rear is a perfect match for the 2004R, (that's what the 4th gear is for....overdrive on an open highway, sweet). That shoud'nt be a problem.

The 2-1/4 pipes are fine, (I also have that). I too fabricated a gutted Monte SS catalytic converter, (not necessary but needed for the down pipe).

My suggestion is that the N/A muffler may not be designed to work with a turbo. It's a single exhuast entry and exit is'nt it? Get a catback exhaust. It's what the aftermarket sells for the turbos. Mine is a catback design but off of an Olds 442.

I may be wrong but my understanding is that back pressure is an important design element for the the EGR and turbo to function properly. (I hope you did'nt plug the EGR, that's bad idea for turbos).

Just throwing that out there as a suggestion, (that the N/A muffler systems are not designed to work with Buick turbo applications).

 

[jimski]

The 3.42 rear is a perfect match for the 2004R, (that's what the 4th gear is for....overdrive on an open highway, sweet). That shoud'nt be a problem.

The 2-1/4 pipes are fine, (I also have that). I too fabricated a gutted Monte SS catalytic converter, (not necessary but needed for the down pipe).

My suggestion is that the N/A muffler may not be designed to work with a turbo. It's a single exhuast entry and exit is'nt it? Get a catback exhaust. It's what the aftermarket sells for the turbos. Mine is a catback design but off of an Olds 442.

I may be wrong but my understanding is that back pressure is an important design element for the the EGR and turbo to function properly. (I hope you did'nt plug the EGR, that's bad idea for turbos).

Just throwing that out there as a suggestion, (that the N/A muffler systems are not designed to work with Buick turbo applications).

Actually it is connected but no vacum lines attacthed

 

[Freddie's Buick]

You should hook it up. When you start hitting the boost and detonation begins to appear, the EGR kicks in to help cool it down.

 

[jimski]

You should hook it up. When you start hitting the boost and detonation begins to appear, the EGR kicks in to help cool it down.

There is no knock that i can hear,The factory ESC is working perfect.I tap at the sensor and it clearly retards the timing so i asume it is working.But i hear you thou,im going to get around hooking it all up.It has been so fun to drive so far havnt been under the hood(i guess that is a good thing )

 

[jimski]

So when i bottom out the pedal around town it should jump to 9psi automatically.It only hits 9psi when im in it and on the highway.??These turbos are pretty small,could i be telling myself i want more allready when not possible from the little engine that could.

 

[Freddie's Buick]

I have'nt gotten out and about with mine yet. But my understanding of the Buick turbo, (which is very limited), is that it starts to work under a load.

Those ESC units are cool. I have one but I have't wired it up yet but I don't have a knock sensor for it either. I'll just keep boost low and water/alcohol inject it and moniter the boost gauage. My EGR is hooked up and functional so there is some protection.

I guess these cars had a duel level of protection from detonation. If you google EGR's and turbo you'll see that most write-ups agree the EGR is very important on turbocharged vehicles.

 

[dr_frankenstein]

It is adjustable,and adjusted.Why would 3.42 make it worst wouldnt the engine work harder with that gear.My exhaust is 2 1/4 this has to be the at least one of the probs... I hollowed out the cat a while back but still has factory muffler.

its eaiser to turn a 3.42 than it is a 3.08.

the engine may have more RPM quicker, but its not increasing the load, its decreasing it.

A.j.

 

[jimski]

its eaiser to turn a 3.42 than it is a 3.08.

the engine may have more RPM quicker, but its not increasing the load, its decreasing it.

A.j.

Is more rpm quicker better?This is kinda changing my load theory..

 

[dr_frankenstein]

Is more rpm quicker better?This is kinda changing my load theory..

Hmm.......im confusing the hell out of ya huh? dammit... im at a loss for words, I know some body else knows what I mean.... right?

or am i alone in the left field?


Before we look at rear gear ratio effects, lets boil down a few details.

Are your secondarys opening?
is your air filter dirty?
what is Intial Timing?
What is total timing?
Color of spark plugs?

all of this can provide clues to the possible lack of boost.

Moving on now,

Hmmm how can I put this in perspective........

imagine a manual trans.... a good ol 3 speed....

now start the car and put it in first.... take off..... the car leaves with out much hesitation and is rolling.... but it will only go as fast as you can rev the engine.

This would be a similar effect for the 3.42s

now on the same car and trans, place it in third..... take off....... the car is a pain to get rolling, takes clutch work and you can hear the engine bogg trying to move the weight...... but now you can go much much faster once rolling.

this would be the simular effect of the 3.08s.

it takes little effort to move the car in first, while in third it requires more energy.... this is how the loads can be view in respects to a 3.42 vs a 3.08.

but yes, the 3.42 is going to feel great - will be fast too!

try something,

put it in gear and hold the brakes as hard as you can, rev the engine as high as you can go without the car sliding, spinning tire or pushing to much....... whats your boost now?

A.j.

 

[jimski]

Hmm.......im confusing the hell out of ya huh? dammit... im at a loss for words, I know some body else knows what I mean.... right?

or am i alone in the left field?


Before we look at rear gear ratio effects, lets boil down a few details.

Are your secondarys opening?
is your air filter dirty?
what is Intial Timing?
What is total timing?
Color of spark plugs?

all of this can provide clues to the possible lack of boost.

Moving on now,

Hmmm how can I put this in perspective........

imagine a manual trans.... a good ol 3 speed....

now start the car and put it in first.... take off..... the car leaves with out much hesitation and is rolling.... but it will only go as fast as you can rev the engine.

This would be a similar effect for the 3.42s

now on the same car and trans, place it in third..... take off....... the car is a pain to get rolling, takes clutch work and you can hear the engine bogg trying to move the weight...... but now you can go much much faster once rolling.

this would be the simular effect of the 3.08s.

it takes little effort to move the car in first, while in third it requires more energy.... this is how the loads can be view in respects to a 3.42 vs a 3.08.

but yes, the 3.42 is going to feel great - will be fast too!

try something,

put it in gear and hold the brakes as hard as you can, rev the engine as high as you can go without the car sliding, spinning tire or pushing to much....... whats your boost now?

A.j.

Im not confused but just saying if 3.42 causes more rpm then it should equal boost putting my load theory to rest thats all but i know load is the factor
secondary are opening up
standard timing on the 3.8
standard adavance timing
regular ac delco they look dark

0 boost on the gauge anny more pedal it will start to spin out