My slow ass DSM build up
09-14-2007, 05:01 PM
#41
1.5 BAR
Join Date: Jun 2003
Location: Plant city,fl
Posts: 1,134
Re: My slow *** DSM build up
Originally Posted by slo_crx1
All that stuff on the b16g with the 7cm^2 hotside is all well and good, but what about the tdo5hr/16g6c with the 10.5cm^2 hot side? I've been trying to find some flow numbers on this sucker and can't seem to come across any. Split tang and reverse rotation sucks *** though, and it looks like either an FP evo-green or a gt30 will be in my future. :P
The hot side your asking about is what Hahn uses and its badass for boost control(i ran a S16g from them for a while).It had a sick topend compared to my fully ported 7cm hotside 14b that saw 27lbs and didnt have the same pull.Tom Noonen didnt run nitrous and its all cool until you get beat by a 16g car.My 16g came with a 34mm flapper and ive heard its a upgrade not factory but i could be wrong.Simply said the 16g is a novice stock feel turbo alot more efficient and if you want something bigger more power to you.Locally mitsu flanged 35r's are getting more popular and producing nice numbers and ive seen them under 1k used if you look hard enough.Honestly for $600 i would go with a 20g but thats just me.I second that the 16g's are best at 300hp anything higher just upgrade.
09-14-2007, 07:49 PM
#42
1.5 BAR
Join Date: Nov 2006
Posts: 1,453
Re: My slow *** DSM build up
Times are changing. 5-7 years ago the 20g was considered too big for a street car (lol), so naturally people gravitated toward the 16g. It has proven to be a fine turbo for daily driven cars that see the track on the weekends and run low-high 12's or higher. Nowadays there are way more options though. It used to just be go to a full Garrett set-up or run a Texas Turbos Frankenstein or some ---- lol. Within the last 5 years all the bolt on 50 trims(and bigger) by Precision, Bullseye, Turbonetics/AGP, etc have come along making it a lot easier for DSMers on a budget to run a much larger turbo that is more efficient in all ways than a MHI turbo. Given more time the 16g will fall from grace.
09-16-2007, 06:13 PM
#43
1.5 BAR
Thread Starter
Join Date: Aug 2003
Posts: 1,194
Re: My slow *** DSM build up
If I'm not mistaken, the EVO 9 comes with a 20G from the factory, and it's not that big.
As for bolt-on hybrids, the turbo I have right now is a Bullseye T04e and I wouldn't recommend it, they're a bunch of monkeys who don't have the slightest clue about turbo design. The exhaust wheel is huge, 74mm. As a comparison the GT35R is a 68mm wheel and the GT40 is a 76mm wheel, ergo a complete mismatch for a T04e compressor.
Then the exhaust housing is tiny, it's just been bored out to accept the freakishly large wheel, in such a manner that there's nothing left of the scroll and all of the exhaust just enters the wheel in one place, where the housing cracks after a short while. The combination of tight housing with no scroll and a big wheel gives you the best of both worlds: lots of lag and HUGE exhaust back pressure.
Then the wastegate actuator is too short, doesn't open the flapper enough for this design of flapper where it's enclosed and needs to swing more than a few degrees to open.
As for bolt-on hybrids, the turbo I have right now is a Bullseye T04e and I wouldn't recommend it, they're a bunch of monkeys who don't have the slightest clue about turbo design. The exhaust wheel is huge, 74mm. As a comparison the GT35R is a 68mm wheel and the GT40 is a 76mm wheel, ergo a complete mismatch for a T04e compressor.
Then the exhaust housing is tiny, it's just been bored out to accept the freakishly large wheel, in such a manner that there's nothing left of the scroll and all of the exhaust just enters the wheel in one place, where the housing cracks after a short while. The combination of tight housing with no scroll and a big wheel gives you the best of both worlds: lots of lag and HUGE exhaust back pressure.
Then the wastegate actuator is too short, doesn't open the flapper enough for this design of flapper where it's enclosed and needs to swing more than a few degrees to open.
09-18-2007, 06:40 PM
#44
3.0 BAR
Join Date: Aug 2003
Location: NE-PA
Posts: 4,666
Re: My slow *** DSM build up
You're right about the Evo9...it does come with a 20g stock, but from what I understand it's not much larger than the 16g used on the Evo8's either. For now the stock turbo will suffice, I'm only looking to make 350awhp sometime down the road.
09-18-2007, 06:50 PM
#45
1.5 BAR
Join Date: Jun 2003
Location: Plant city,fl
Posts: 1,134
Re: My slow *** DSM build up
Originally Posted by slo_crx1
You're right about the Evo9...it does come with a 20g stock, but from what I understand it's not much larger than the 16g used on the Evo8's either. For now the stock turbo will suffice, I'm only looking to make 350awhp sometime down the road.
09-18-2007, 06:59 PM
#46
1.0 BAR
Join Date: Oct 2006
Posts: 556
Re: My slow *** DSM build up
Originally Posted by baldur
I know you _can_ push them up to that power level on stock internals and stock compression ratio. However on pump gas you lose efficiency at high boost due to retarded timing on a high compression ratio motor.
09-18-2007, 07:33 PM
#48
3.0 BAR
Join Date: Oct 2006
Posts: 2,330
Re: My slow *** DSM build up
Originally Posted by losesomethinbra
I thought you retard timing, and add boost... Isnt that what you're supposed to do? When exactly do you lose this efficiency and why would I care if I have a huge turbo that can handle more boost anyways? Not trying to be a dick, just wanna see where you got the info
09-18-2007, 07:43 PM
#49
1.5 BAR
Thread Starter
Join Date: Aug 2003
Posts: 1,194
Re: My slow *** DSM build up
Picture this. You only have about 20 degrees of crank rotation during the combustion stroke where the pressure will convert into useful power, and the peak pressure has to be in the area of 10 degrees after TDC (depending on rod-stroke ratio, pin offset and such factors) for maximum efficiency, in other words you have to manage to complete most of the combustion by then to make good efficient power.
You retard ignition with higher pressure because the combustion becomes faster at higher pressure.
Now, there comes a point where you start having to retard the ignition more than the combustion speed dictates, in order to reduce the peak pressure because it's detonating. This is where you start losing power because the combustion is no longer delivering it's peak pressure in the right time of the cycle in order to deliver the strongest force into the crank and complete most of the expansion before the exhaust valve opens.
To offset this you can do two things: you can increase the detonation threshold of the mixture you're feeding the engine by using a higher octane fuel, colder air and a richer mixture (which cools things down but delivers another problem: it burns slower and going too rich means it won't complete combustion early enough to make power)
Another way is to reduce cylinder pressure by reducing the compression ratio.
Of course for biggest power you want high compression and high octane fuel. High octane fuel is not available to run in a street car so you need to compensate otherwise to make big power. I've seen several 4 bangers make 500-600bhp on premium unleaded fuel and be able to do so on an engine dyno for extended periods. Try doing this with a high compression ratio.
A lower compression ratio also generally reduces mechanical stress, which is why turbo diesels, especially big boost ones have a lower compression ratio than their naturally aspirated counterparts, even though diesels don't have any detonation.
And yes, turbo life is reduced when you move too far right on the map, where you start needing higher rpms to maintain the same pressure ratio. This also increases the back pressure and compressor outlet temperature.
You retard ignition with higher pressure because the combustion becomes faster at higher pressure.
Now, there comes a point where you start having to retard the ignition more than the combustion speed dictates, in order to reduce the peak pressure because it's detonating. This is where you start losing power because the combustion is no longer delivering it's peak pressure in the right time of the cycle in order to deliver the strongest force into the crank and complete most of the expansion before the exhaust valve opens.
To offset this you can do two things: you can increase the detonation threshold of the mixture you're feeding the engine by using a higher octane fuel, colder air and a richer mixture (which cools things down but delivers another problem: it burns slower and going too rich means it won't complete combustion early enough to make power)
Another way is to reduce cylinder pressure by reducing the compression ratio.
Of course for biggest power you want high compression and high octane fuel. High octane fuel is not available to run in a street car so you need to compensate otherwise to make big power. I've seen several 4 bangers make 500-600bhp on premium unleaded fuel and be able to do so on an engine dyno for extended periods. Try doing this with a high compression ratio.
A lower compression ratio also generally reduces mechanical stress, which is why turbo diesels, especially big boost ones have a lower compression ratio than their naturally aspirated counterparts, even though diesels don't have any detonation.
And yes, turbo life is reduced when you move too far right on the map, where you start needing higher rpms to maintain the same pressure ratio. This also increases the back pressure and compressor outlet temperature.
09-18-2007, 09:15 PM
#50
0.0 BAR
Join Date: Dec 2005
Posts: 0
Re: My slow *** DSM build up
Originally Posted by baldur
Picture this. You only have about 20 degrees of crank rotation during the combustion stroke where the pressure will convert into useful power, and the peak pressure has to be in the area of 10 degrees after TDC (depending on rod-stroke ratio, pin offset and such factors) for maximum efficiency, in other words you have to manage to complete most of the combustion by then to make good efficient power.
You retard ignition with higher pressure because the combustion becomes faster at higher pressure.
Now, there comes a point where you start having to retard the ignition more than the combustion speed dictates, in order to reduce the peak pressure because it's detonating. This is where you start losing power because the combustion is no longer delivering it's peak pressure in the right time of the cycle in order to deliver the strongest force into the crank and complete most of the expansion before the exhaust valve opens.
To offset this you can do two things: you can increase the detonation threshold of the mixture you're feeding the engine by using a higher octane fuel, colder air and a richer mixture (which cools things down but delivers another problem: it burns slower and going too rich means it won't complete combustion early enough to make power)
Another way is to reduce cylinder pressure by reducing the compression ratio.
Of course for biggest power you want high compression and high octane fuel. High octane fuel is not available to run in a street car so you need to compensate otherwise to make big power. I've seen several 4 bangers make 500-600bhp on premium unleaded fuel and be able to do so on an engine dyno for extended periods. Try doing this with a high compression ratio.
A lower compression ratio also generally reduces mechanical stress, which is why turbo diesels, especially big boost ones have a lower compression ratio than their naturally aspirated counterparts, even though diesels don't have any detonation.
And yes, turbo life is reduced when you move too far right on the map, where you start needing higher rpms to maintain the same pressure ratio. This also increases the back pressure and compressor outlet temperature.
You retard ignition with higher pressure because the combustion becomes faster at higher pressure.
Now, there comes a point where you start having to retard the ignition more than the combustion speed dictates, in order to reduce the peak pressure because it's detonating. This is where you start losing power because the combustion is no longer delivering it's peak pressure in the right time of the cycle in order to deliver the strongest force into the crank and complete most of the expansion before the exhaust valve opens.
To offset this you can do two things: you can increase the detonation threshold of the mixture you're feeding the engine by using a higher octane fuel, colder air and a richer mixture (which cools things down but delivers another problem: it burns slower and going too rich means it won't complete combustion early enough to make power)
Another way is to reduce cylinder pressure by reducing the compression ratio.
Of course for biggest power you want high compression and high octane fuel. High octane fuel is not available to run in a street car so you need to compensate otherwise to make big power. I've seen several 4 bangers make 500-600bhp on premium unleaded fuel and be able to do so on an engine dyno for extended periods. Try doing this with a high compression ratio.
A lower compression ratio also generally reduces mechanical stress, which is why turbo diesels, especially big boost ones have a lower compression ratio than their naturally aspirated counterparts, even though diesels don't have any detonation.
And yes, turbo life is reduced when you move too far right on the map, where you start needing higher rpms to maintain the same pressure ratio. This also increases the back pressure and compressor outlet temperature.
essentially, deisels run ON detonation.
