How high can we boost
Jan 20, 2008, 10:22 AM
#46
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I have already read the information on garretts website, thanks for the link. It was a good refresher.
I'm growing weary. compressor maps are just that, maps. they are nonlinear for a reason: many variables make up the potential for the turbo. If you want to believe you can just put a bigger turbo on to make more power at 8psi then feel free to start throwing them on man
I'd be concentrating on the more important parts of the kit though, because the turbo should be matched to the output and then left alone.
maybe I have misunderstood, I'd be willing to admit that, but only if you promise to stop calling me stoopid
get a grip man, and act like your old enough to have an adult conversation
I'm growing weary. compressor maps are just that, maps. they are nonlinear for a reason: many variables make up the potential for the turbo. If you want to believe you can just put a bigger turbo on to make more power at 8psi then feel free to start throwing them on man
I'd be concentrating on the more important parts of the kit though, because the turbo should be matched to the output and then left alone.maybe I have misunderstood, I'd be willing to admit that, but only if you promise to stop calling me stoopid
get a grip man, and act like your old enough to have an adult conversationI will try to explain this one last time to you. Bigger compressors move more air at the same psi as a smaller turbo. To help explain this, we will use my engine and a lineup of turbos ALL OF WHICH WILL BE AT 20PSI.
Numbers are within 5-10whp giving mods.
Ko3 = 190whp
gt28r = 280whp
gt28rs = 300whp
50trim = 320whp
gt2871r = 325whp
gt3071r = 375whp
and so on… As boost pressures increase, the difference between turbos will become larger.
There, now I have again answered the org, topic and showed you how psi is just pressure, not the amount of CFM moved. That’s why turbos are rated in hp/cfm, its based on the compressor and turbine wheels.
Jan 20, 2008, 10:49 AM
#47
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Hate to jump into your tread but the comment abotu the diffrent turbos and the boost is true diffrent turbos have diffrent VE i went from stock evo turbo to a GT35r and 20 psi on a 16g is way diffrent then 18 psi on a 35r
Jan 20, 2008, 05:00 PM
#49
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I will try to explain this one last time to you. Bigger compressors move more air at the same psi as a smaller turbo. To help explain this, we will use my engine and a lineup of turbos ALL OF WHICH WILL BE AT 20PSI.
Numbers are within 5-10whp giving mods.
Ko3 = 190whp
gt28r = 280whp
gt28rs = 300whp
50trim = 320whp
gt2871r = 325whp
gt3071r = 375whp
and so on… As boost pressures increase, the difference between turbos will become larger.
There, now I have again answered the org, topic and showed you how psi is just pressure, not the amount of CFM moved. That’s why turbos are rated in hp/cfm, its based on the compressor and turbine wheels.
Numbers are within 5-10whp giving mods.
Ko3 = 190whp
gt28r = 280whp
gt28rs = 300whp
50trim = 320whp
gt2871r = 325whp
gt3071r = 375whp
and so on… As boost pressures increase, the difference between turbos will become larger.
There, now I have again answered the org, topic and showed you how psi is just pressure, not the amount of CFM moved. That’s why turbos are rated in hp/cfm, its based on the compressor and turbine wheels.
you are only changing the turbo and you come up with 190 with one option and 375 with another option? I know it sounds like I am beating a dead horse, but I want to be 100% clear on this
just changing the turbo will net that much difference at 20psi?
Jan 20, 2008, 05:36 PM
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that other guy is probably running 870cc or 1000cc injectors to feed his car since he is moving far more air.
Last edited by cincy; Jan 20, 2008 at 05:38 PM.
Jan 20, 2008, 08:41 PM
#51
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completely off/on topic..
the company is called aftershock. I know a friend who asked them legitmit questions about their setup. and they disregarded the questions and more or less insulted him.
he replied with actual facts supporting his questions... with a bit of attitude (ill admit it) and he was temp banned from the site.
the company is called aftershock. I know a friend who asked them legitmit questions about their setup. and they disregarded the questions and more or less insulted him.
he replied with actual facts supporting his questions... with a bit of attitude (ill admit it) and he was temp banned from the site.
Jan 21, 2008, 03:48 AM
#52
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No, you will need larger injectors. Stock uses 317cc @3bar of pressure. You will need atleast 630cc injectors at 3bar to handle the increase in air. More air means you need more fuel. You should also have a high flowing turbo manifold, larger ic and piping to handle the added flow. Otherwise you will choke the turbo
that other guy is probably running 870cc or 1000cc injectors to feed his car since he is moving far more air.
that other guy is probably running 870cc or 1000cc injectors to feed his car since he is moving far more air.
thanks, that was the whole point of my argument. your turbo might allow for more power, but you aren't going to get more power by changing to a larger turbo; the kit is a sum of it's parts. why was that so hard to understand when BOTH people who were initially discussing this came to the same conclusion many posts ago?
not sure why you didn't read those posts, but they are there.moving on...
can't find aftershock on teh google(well, I can but I'm not looking for alcohol), do you have a link to website by any chance? maybe a link to the thread you are talking about or the members name so I can search for the thread myself? are they paying vendors on here? that usually gives them a leg up against anyone posting in a thread they started.
Jan 21, 2008, 04:41 AM
#53
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No i did some supporting mods except the motor's internals. I did the fuel system intercooler and thats about it to start and it a billion times diffrent.
Jan 22, 2008, 01:44 AM
#55
Just a quick one here and I have only just looked at the last few pages of this and it may help out with a few more questions and answers...
I currently have a T28 turbo and run 4 x 390cc injectors with the Haltech E8 and run at 12psi - we can not up the boost any more than this due to the exhaust being my biggest restriction it is only a 21/2" press bent... now if I go to a bigger exhaust one (3" mandrel) that is going to allow all the gassess to be pushed out more easily it will dramaticly reduce back pressure and we can up the boost levels
Just adding a bigger turbo and bigger injectors does not give you unlimited power you need to make sure that everything else matches up also keep in mind that a turbo cam shaft will allow a longer duration as well so that you can get more longer revs out of the engine I know mine stops making power at 5500rpm but a better designed cam should allow power to be continually made up to 7000rpm
I currently have a T28 turbo and run 4 x 390cc injectors with the Haltech E8 and run at 12psi - we can not up the boost any more than this due to the exhaust being my biggest restriction it is only a 21/2" press bent... now if I go to a bigger exhaust one (3" mandrel) that is going to allow all the gassess to be pushed out more easily it will dramaticly reduce back pressure and we can up the boost levels
Just adding a bigger turbo and bigger injectors does not give you unlimited power you need to make sure that everything else matches up also keep in mind that a turbo cam shaft will allow a longer duration as well so that you can get more longer revs out of the engine I know mine stops making power at 5500rpm but a better designed cam should allow power to be continually made up to 7000rpm
Apr 15, 2008, 05:36 AM
#57
Evolving Member
I'm a bit late on this thread but any clue what a good number is with a full rebuild shy of rods and crank they will be the only stock parts left in my engine.
Apr 21, 2008, 04:08 PM
#58
I looked at the size of some of the innards. My opinion just poking around in there plus looking at some of the basics like compression and rod/stroke ratio is that 10 is probably a good maximum for the stock engine.
Don't be overly worried about exhaust size. I've made over 500whp on a 2.5" exhaust and the backpressure was less than 1 psi at the downpipe. A 2.5" exhaust is good for over 600hp. Charge piping I've made 500whp with 2.25 piping so again that's not a huge restriction. A piece of 2" charge piping flowed more than enough to rail my flowbench at 500cfm.
Turbo size obviously has a big impact on my blank statement of 10 psi. Smaller turbos have a tendency to stress the engine more so if you put a T25 you might have problems at 10psi. There are a few reasons for this:
a) More exhaust backpressure means your exhaust valves are hotter - this is the primary cause of detonation in a properly tuned engine.
b) Boost at lower RPMs - the pistons are moving slower and the cylinder pressures rise faster as the flame front travels. This leads to more liklihood of detonation and if the rods are weak can cause the rods to yield. I've seen more than one rod break at low RPMs and high boost. I can't say why because I didn't tune those particular cars but that's my experience. On my old mazda 323 I tried to blow it up - detonated all the day down the 1/4 mile for an entire day without a problem. Then one shot of 15 psi at low RPM and bam it bent a rod... still drove it home like that :P
c) Compressor wheel has to spin faster to move the same amount of air and therefore heats the charge more. Now most people buy a FMIC that's about 3x larger than they need so this has probably less impact but for sure I've seen much higher intake air temps on small turbo cars.
You can't even figure out the turbo size by stating it's a T3/T4 - another commonly misunderstood fact. Is it a T3/T04B stage 1 0.48AR? Or is it a T3/T04E 60 trim 0.70AR with a stage 4 wheel? One is a 250hp turbo and one is a 500hp turbo.
Hope that helps some.
-Michael
Don't be overly worried about exhaust size. I've made over 500whp on a 2.5" exhaust and the backpressure was less than 1 psi at the downpipe. A 2.5" exhaust is good for over 600hp. Charge piping I've made 500whp with 2.25 piping so again that's not a huge restriction. A piece of 2" charge piping flowed more than enough to rail my flowbench at 500cfm.
Turbo size obviously has a big impact on my blank statement of 10 psi. Smaller turbos have a tendency to stress the engine more so if you put a T25 you might have problems at 10psi. There are a few reasons for this:
a) More exhaust backpressure means your exhaust valves are hotter - this is the primary cause of detonation in a properly tuned engine.
b) Boost at lower RPMs - the pistons are moving slower and the cylinder pressures rise faster as the flame front travels. This leads to more liklihood of detonation and if the rods are weak can cause the rods to yield. I've seen more than one rod break at low RPMs and high boost. I can't say why because I didn't tune those particular cars but that's my experience. On my old mazda 323 I tried to blow it up - detonated all the day down the 1/4 mile for an entire day without a problem. Then one shot of 15 psi at low RPM and bam it bent a rod... still drove it home like that :P
c) Compressor wheel has to spin faster to move the same amount of air and therefore heats the charge more. Now most people buy a FMIC that's about 3x larger than they need so this has probably less impact but for sure I've seen much higher intake air temps on small turbo cars.
You can't even figure out the turbo size by stating it's a T3/T4 - another commonly misunderstood fact. Is it a T3/T04B stage 1 0.48AR? Or is it a T3/T04E 60 trim 0.70AR with a stage 4 wheel? One is a 250hp turbo and one is a 500hp turbo.
Hope that helps some.
-Michael
Apr 22, 2008, 09:55 AM
#59
Evolved Member
To be clear here they were not legit questions and you friend used foul language I am on the site as well....so be very clear and fair....i was not totally impressed the response either but i was told that your friend was a trouble maker from past posts.....
Aftershock is still around they are merging with another Ottawa company....no website from what I know.
Aftershock is still around they are merging with another Ottawa company....no website from what I know.
completely off/on topic..
the company is called aftershock. I know a friend who asked them legitmit questions about their setup. and they disregarded the questions and more or less insulted him.
he replied with actual facts supporting his questions... with a bit of attitude (ill admit it) and he was temp banned from the site.
the company is called aftershock. I know a friend who asked them legitmit questions about their setup. and they disregarded the questions and more or less insulted him.
he replied with actual facts supporting his questions... with a bit of attitude (ill admit it) and he was temp banned from the site.
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