Maximum safe BHP for stock 1.5 with turbo

[TonyHanscomb]

Anyone know what power output to expect (or risk) just adding a good turbo to the stock 1.5 Yaris engine?
As far as I can ascertain the boost can just be turned up to produce whatever power one wants, until it self destructs.
It would be good to know how much it can take?

Also is there any inherent weaknesses that can be eliminated to allow higher boosts, such as forged pistons, different crank, special rods?

[cdydjded]

Its an unknown #, there are less than 25 boosted cars here & most are making 125-175hp with stock engines.

as for your second question, any & all internal upgrades will allow for higher boost levels. only pistons, rods & block sleeves are avaialable.

[Blown_xa]

from my experience, 150whp was the limit (on our dyno). I blew up 4 or 5 stock motors unfortunately (because I was greedy ) before building one. 2 of those were not directly related to power output... I once had my meth nozzle clog so detonation occured , thats why I always recommend a flow rate gauge to customers running wmi. If the car is tuned mbt with meth, and the pump fails or line blows off.... motor go boom even a built one.

150whp is still fun in our small cars for sure, considering 86whp stock! Ive posted videos of track time with 130whp and still passed evos and s2000's . A little hp gain counts for a lot on a car around 2300lbs.

[cali yaris]

there are less than 25 boosted cars here & most are making 125-175hp with stock engines.

yep, that's just about the complete answer right there.

I ran 183 whp for about 9 months on the stock motor, but without a tune. I lost a little compression in one piston, but with a good tune that might not have happened.

[thebarber]

its likely more about the psi you're pushing with the turbo or superchager vs the actual at-wheel hp

i think 9-ish psi would be the max max on our already 10.5:1 compression engines...

[mightyMax95]

Originally Posted by thebarber

its likely more about the psi you're pushing with the turbo or superchager vs the actual at-wheel hp

i think 9-ish psi would be the max max on our already 10.5:1 compression engines...

hate to do this to you :hide: but psi is irrelevant, flow is key here.

little bitty turbo can run high pounds psi and big turbos less pounds psi without blowing. this is coming from a Maxima forum where some guys reliably run 15 pounds of boost while others blow at 10, all on a stock 10:1 cr motor (vq30). the key thing is to use an appropriate size turbo with flow characteristics that will fit the application.

however, by far the most important thing is a good tune.

[cdydjded]

Originally Posted by thebarber

its likely more about the psi you're pushing with the turbo or superchager vs the actual at-wheel hp

i think 9-ish psi would be the max max on our already 10.5:1 compression engines...

9lbs on with a T28 (what Im using) is not the same as 9lbs with a GT2554R (what Garm is using)........

[Yoda]

Originally Posted by Blown_xa

from my experience, 150whp was the limit (on our dyno). I blew up 4 or 5 stock motors unfortunately (because I was greedy ) before building one. 2 of those were not directly related to power output... I once had my meth nozzle clog so detonation occured , thats why I always recommend a flow rate gauge to customers running wmi. If the car is tuned mbt with meth, and the pump fails or line blows off.... motor go boom even a built one.

150whp is still fun in our small cars for sure, considering 86whp stock! Ive posted videos of track time with 130whp and still passed evos and s2000's . A little hp gain counts for a lot on a car around 2300lbs.

Got to agree here. For safety and longevity all the Toyota forums I have seen said the same thing. But I still think if it's tuned really well then 8psi no problem. By tuned really well I mean pro tuned. There was a guy that ran a test(will try to dig up the website later) that showed 5-6psi was safe but when he cranked it up to 8psi engine blew after 6 months of tracking. It also depends on how you drive your car also. How often will you see high rpm?
Street or track use?

[Blown_xa]

Originally Posted by Yoda

Got to agree here. For safety and longevity all the Toyota forums I have seen said the same thing. But I still think if it's tuned really well then 8psi no problem. By tuned really well I mean pro tuned. There was a guy that ran a test(will try to dig up the website later) that showed 5-6psi was safe but when he cranked it up to 8psi engine blew after 6 months of tracking. It also depends on how you drive your car also. How often will you see high rpm?
Street or track use?

I see high rpm often, track it a lot. It's also my DD with 120,000 miles on it.
Yea somebody brought up the point that boost is irrelivent, which is true. As I put the same whp down on my current turbo at 9psi as my Greddy at 20psi.

[cali yaris]

9lbs on with a T28 (what Im using) is not the same as 9lbs with a GT2554R (what Garm is using)........

I think you meant was I WAS using -- currently using a GT28 disco potato.

[Blown_xa]

Originally Posted by cali yaris

I think you meant was I WAS using -- currently using a GT28 disco potato.

haha, i was waiting for that. where did the name disco potato come from? i almost wanna buy it just to say i gotta disco potato under my hood cause it sounds cool.

[cdydjded]

Originally Posted by cali yaris

I think you meant was I WAS using -- currently using a GT28 disco potato.

Opps! I was doubting myself when I was putting GT255R......

[cdydjded]

Originally Posted by Blown_xa

haha, i was waiting for that. where did the name disco potato come from? i almost wanna buy it just to say i gotta disco potato under my hood cause it sounds cool.

This turbo has a very interesting story behind it, here's the full article and story from Sport Compact Car:

Elsewhere in this issue you will read about how to choose the right turbo for your car. The explanation uses compressor maps, math, and the need to at least pretend you understand some complex engineering concepts.

Here's another method.

Step 1: Drive a car with a really good turbo match.
Step 2: Build a similar car.

A year and a half ago, we drove a very unlikely Sentra. Dubbed the Disco Potato for its unique combination of psychedelic color-shifting paint and unfortunate Jerry Hirshberg styling, the car was the culmination of the clandestine efforts of a few very driven engineers.

The story starts with Dan Passe who, at the time, was a Nissan PR genius with a penchant for bending rules. He conveniently "lost" the paperwork for a 1.8-liter Sentra which Nissan Design International had modified for the L.A. Auto Show. The car quietly landed in the hands of Nissan engineers Steve Mitchell and Mike Kojima.

Meanwhile, a few miles away at Garrett, turbo engineer Jay Kavanagh wanted to boost his Miata. Having full access to the newest Garrett technology, he concocted a physically small turbo with a ball-bearing center section and internal aerodynamics 20 years more modern than the T3/T4 standard the aftermarket is used to.

A few cubicles from Kavanagh, Rob Cadle, a good friend of Mitchell and Kojima, realized Kavanagh's Miata turbo would be perfect for the SR20DET the Nissan boys were planning for the Sentra. He brewed up a turbo, stuffed it under his shirt, and went out the back door.

Jim Wolf Technology built a very mild SR20 for the Sentra, making it functionally equivalent to a stock Japanese-spec SR20DET. The turbo was installed, and amazing things started happening. The car's power was impressive, 280 hp at the wheels, but not earth-shattering. The driving experience however, was. Throttle response was excellent, turbo lag virtually non-existent, and the tire-shredding power was easily modulated. The turbo spooled up early, making so much torque, that the best quarter-mile time (13.7 at 104.5 mph) was achieved launching in second gear.

Mitchell brought the Disco Potato to the Ultimate Street Car Challenge in 2001, and placed an impressive fourth overall. The rest of the time, the car was stashed away in Nissan USA's service garage and used strategically as an attitude adjustment tool. Whenever Nissan or Garret executives needed an injection of gasoline in their veins, they were offered the keys. They would inevitably come back grinning from ear to ear and breathing heavily, eager to bring horsepower to the masses.

There's no telling how many decisions were nudged in the right direction by the Disco Potato, but it did prompt two that are critical to this story. We drove the car for a week, including a 1,000-mile road trip and track day at Thunderhill Raceway. After outrunning every car at the track, and blasting down the freeway at 140 mph, we knew we must have that engine. Ours, however, had to be in a rear-drive chassis. Thus was born Project Silvia.

Several Garret executives also experienced the Potato. They were so impressed, they decided to produce the turbo, double the engineering staff in the aftermarket department, and start applying this modern Garrett technology to a whole range of aftermarket turbos. Technically, this is a GT28R with a 62 trim compressor (.60 A/R) and a 76 trim turbine (.86 A/R), but you don't need to know that. Ask anyone at Garrett for a Disco Potato turbo, and this is what you'll get.

[Evangelion335]

Originally Posted by cdydjded

9lbs on with a T28 (what Im using) is not the same as 9lbs with a GT2554R (what Garm is using)........

Can someone explain this to me?

It was my understanding that the # measurement was accurate right untill it passes trough the throttle body.

Flow is an important matter, but only because you can create a bottle-necking effect that will rob you of available o2 into the engine.

The 9lb rating is going to be 9lbs no matter what the size of the turbo is. In the same sense that you can have a gallon of water thats pressurized at 9lbs as well as having an oz of water pressurized at 9lbs. Turbo sizes are relevant to the volume of air intake the engine requires not so much the #s required (this isnt a hard an fast rule).

Smaller turbos are ideal for smaller engines because:
1: A smaller turbo has less mass at the turbine meaning that it will take less force to achieve maximum rotations and therefore less time to achieve desired pressure.
2: Because you engine is smaller (1.5l) the actual internal volume of the cylinder requires less oxygen to reach the desired pressurization.
3: a large turbo and a small turbo running at identical pressures will produce the same horsepower gains. The "power loss" becomes an issue because you have selected a turbo that is limiting your maximum flow rate and spooling time. This can wildly effect torqe curves and produce a torqe curve that will become murder on trackday.

Can someone read that and tell me if ive got the theory right?

[eTiMaGo]

thanks for the history lesson on the disco potato, I feel enlightened :D

Some time back I talked to the local TRD distributors about turboing my car, and they explained the reason why the TRD turbo'ed 1NZs are limited to about 140hp is that above this level, the internals are not up to the job. I assume this means the engine will only last 180,000 miles instead of 250,000 (or whatever, just illustrating the difference), since these guys do give a warranty coverage, but that is the most official limitation I have seen/heard.

[cdydjded]

Originally Posted by Evangelion335

Can someone explain this to me?

It was my understanding that the # measurement was accurate right untill it passes trough the throttle body.

Flow is an important matter, but only because you can create a bottle-necking effect that will rob you of available o2 into the engine.

The 9lb rating is going to be 9lbs no matter what the size of the turbo is. In the same sense that you can have a gallon of water thats pressurized at 9lbs as well as having an oz of water pressurized at 9lbs. Turbo sizes are relevant to the volume of air intake the engine requires not so much the #s required (this isnt a hard an fast rule).

Smaller turbos are ideal for smaller engines because:
1: A smaller turbo has less mass at the turbine meaning that it will take less force to achieve maximum rotations and therefore less time to achieve desired pressure.
2: Because you engine is smaller (1.5l) the actual internal volume of the cylinder requires less oxygen to reach the desired pressurization.
3: a large turbo and a small turbo running at identical pressures will produce the same horsepower gains. The "power loss" becomes an issue because you have selected a turbo that is limiting your maximum flow rate and spooling time. This can wildly effect torqe curves and produce a torqe curve that will become murder on trackday.

Can someone read that and tell me if ive got the theory right?

Practice always beats theory:
http://www.turbobygarrett.com/turbob...ch_center.html

Read the above & all your questions will be answered....

[cali yaris]

^ +1 good link to bookmark, everyone.

[H3LlIoN]

homemadeturbo.com is another great forum for forced induction specific theory and discussion, free to reg.