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HIGH boost T3 guys...


Guest ON3GO

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Okay..

i really only know of 2 people that boost 18-20psi on the stock T3..

Thumper, and Jersey..

Im not sure about Jersey as i never heard of anything happening to his turbo, but Ted (thumper) is on his 4th or so turbo already in maybe 2 or so months.

now yes there all junkyard turbos, but a few had little to no shaft play and looked real good. he is boosting alot and beating the crap out of his car alot, but in my mind there has to be something more to it to make this happen.

 

is the oil feed line just not good enough for that high of boost, oil pump? gotta be something.

 

reason why i asked is i ran my T3 from 15-18psi for 2 months before i tore the whole car down and didnt have a problem, and that turbo was a 278+K mile turbo off my donar engine/car. i didnt race the car as much as ted does but i did floor it all the time and beat the crap out of it allllll the time.

 

my engine is pretty much ALL together, just waiting on the Toga H-V turbo oil pump and really thats it. i much rather find a answer saying "ya the oil line sucks, or etc etc etc" while i have the chance to change something.

 

So high high boost T3 guys.. whats your thoughts..

 

mike

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Guest bastaad525

I think it's just a matter of luck... I dont think it's the oil feed because as I understand it the oil passes thru there very slowly anyways.

 

18-20psi (actually more like 20psi + since most intercoolers have some pressure drop across them) is just spinning the turbo REALLY fast compared to what it was designed for I think. Then again, there are guys running other kinds of turbos that run 20-30psi... maybe they are all ball bearing turbos or what I dunno.

 

I'd like to hear some answers as well on this one, because I've been nervous about turning mine up past 14psi because I dont want to be replacing the turbo any time soon.

 

And anyways, what has happened to Jersey haven't heard from him in a while.

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Only thing about my turbos were on my first turbo, my oil pump was bad. On the second and 3rd the oil pressure was still low due to restriction in the oil cooler. And the 4th was due to running 18-20 psi with a n/a oil pump. I'm not saying that the t3 is reliable at these boost levels just saying my case had other factors. The ghetto beast ran 4 months at 18-20 psi before I removed the engine. The turbo had very little shaft play so it can hold it just not for very long.

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  • 2 weeks later...

even though the turbo is making this much boost it is overheating the air and you still need a larger volume of air at a lower temp.if you run this much boost you need a wide band 02 to make sure the engine is fueled properly.if the efi cant follow the boost then you get boom.but if you like to work on your car alot try it.your timing needs to be about 22 or 24 btdc at boost .if you can make a 12to 1 af and have timing at a good setting it might live for awhile.a good cruutch is race gas.when i take my car to open track days i run race gas all day.usually run 14 psi but that is for 1/2 hour at a time.also run a 160 thermostat.

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You are seriously over-spinning the turbo. The last 2 T3's I had on my car I turned the exhaust wheel and shaft the prettiest shade of blue. That was at 20-23 psi. I got about 6 months out of each, but I went to the track alot. The problem is the overspinning...you just can't get enough oil to it no matter what when you spin them that hard. I finally went to a hybrid, and then started killing it and went to a T-70...haven't killed it yet...

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im going Holset HY35... if not then ill go bigger to a full T4..

right now im just trying to figure out what i want to do with this car.

its sorta a mess... show car/drag car/road racer... hahaha i have no direction.. my highschool teachers were right.

 

mike

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Guest bastaad525

so then is there an agreed maximum 'relatively safe' boost level? We all seem to agree that 15 is still okay, and 20 is killing it... how about 17-18?

 

 

Another thing people never seem to think of or discuss... remember when you run your turbo at say, 15 psi, that's 15 psi you are most likely measuring at the manifold, but remember you are losing some boost thru the I/C. So your turbo may actually be putting out 16-18psi. That's why I never even felt comfortable with 15 because I knew I was getting at least 2 psi of pressure drop so would actually be running like 17.

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A good spearco core will have 1lb or less pressure drop across the core...if you're using something like astarion IC like I was when running my t3, expect about 5lbs or more. They are really restrictive...especially if you're still using the 1 and 7/8 inlet and outlet pipes that they came with factory. I guess you could say my turbo wa probably pushing close to 30psi as I forgot about the pressure drop across the core.

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I ran a JDM turbine housing, and could get full boost at 1500rpm, and the unit would surge badly at 21psi. But not at 20.

 

The overspeed is one item, but that is only a matter of balance. The balance really isn't what kills them, the half thrust bearing it what kills them!

 

The load you place on the compressor wheel (simply put, designed for 5 psi, now running 4X that) quadruples the bearing loads on a thrust bearing that is marginal in the first place.

 

As the bearing WEARS (and it DOES WEAR) the axial movement of the impeller increases. On lift-throttle event where the rotor assembly makes a full available axial movement and SLIGHTLY kisses the housing, and that is the beginning of the end.

 

What was in exquisite balance previously is now out of balance, nad starts the beating bearing road to failure.

 

Industrial turbines have "startup rubs" all the time, and run forever because their bearings are overdesigned. But in an automotive turbocharger design practice is a little less.... So you have a half-thrust bearing instead of a 360 degree thrust bearing.

 

And no matter where it goes first, turbine or compressor, once it kisses due to wear you are on the road to ruin.

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I have a Garrer T3 that I ripped off a Ford Escord Cosworth 4wd on my VW Corrado. It's an 1.8l engine and I'm running 19 psi pressure. It's still spinning and have been for over a year now. Quite happy with it.

 

 

One problem is that people sometimes dont let the oil cool down the turbo enough before engine is turned off.

This will burn the oil inside the turbo if it's to hot = leading to a "plug"

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here's my problem..

 

with the stock L28 HANDLE 18psi very well??!

 

I have MSnS so I have good fuel management and timing.. BUT.. can the motor handle it?!

 

I am afraid of turning up the boost to even 14psi.. hell the headgasket could blow or pistons could go right through the block>?!

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here's my problem..

 

with the stock L28 HANDLE 18psi very well??!

 

I have MSnS so I have good fuel management and timing.. BUT.. can the motor handle it?!

 

I am afraid of turning up the boost to even 14psi.. hell the headgasket could blow or pistons could go right through the block>?!

 

 

I did 22 psi on a stock junkyard block. Not stock turbo. Would of done moe if I was looking for big numbers. Boost isn't the limiting factor, detonation is. Bppst can lead to det just as too much timing can though. You can run C16 and 30 psi with stock pistons and it would be safer than 20 psi on 91 octane.

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  • 2 months later...
I did 22 psi on a stock junkyard block. ....... You can run C16 and 30 psi with stock pistons and it would be safer than 20 psi on 91 octane.

 

Clifton, when you say 'stock jy block,' are you talking about an l28et, or a stock n/a block and n/a pistons like what Prox and I are running? Like Prox, I'm worried that even when properly tuned, the n/a motors will fail at a certain boost level/HP due to their pistons having thinner ring lands, among other factors. Running the n/a cam is also something that concerns me. What is your take on our situation? Also, what is C16? -Mike

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http://www.vpracingfuels.com/vp_01_fuels.html

 

C16

Used in turbocharged engines, blown engines and nitrous applications with CRs up to 17:1. Recommended by the top nitrous oxide companies. Spec Fuel for NHRA Comp Eliminator.

 

• Color: Blue

• Motor Octane: 117

• Specific gravity: .735 at 60° F

 

 

Dave

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