20psi on pump gas, if you dont know, dont answer...

[QWIKSTRIKE]

race gas is still VERY cheap here- 110 for $5.25/gal, 116 for $10/gal....ironic that it doesn't go up nearly as fast as pump gas....

Tell me about this little tidbit drjonze. You would think race gas to go to the moon, but it hasn't

 

[drjonez]

Tell me about this little tidbit drjonze. You would think race gas to go to the moon, but it hasn't

it's called the big oil companies lining their pockets....

 

[Doward]

Actually, the 'sweet spot' on that 67mm turbo, is at low boost. Look at our motor, pushing 12 psi. It's right on the edge of that 76% efficiency line

The thing of it is that you can push more pressure than most turbos, and do so without heating the intake charge excessively.

Personally, on a 7M running 7500rpm, I would run no more than 26psi (that is on the 70% efficiency line) maximum from the turbocharger.

Daily I would run 18psi running 7200rpm (and sit happily at that 74% efficiency island).

Actually, that's exactly what I'm going to run on my setup, LOL

Wastegate = 12-14psi
Daily Driven = 18psi pump gas tune (with cams/ported head)
Race Only (and dyno run) = 26psi + 50 shot of nitrous (this will not be until after I have determined the maximum fuel flow available from my 680ccs - I'll most likely need 750+cc injectors with an external pump at that level)

If you want an idea of the power levels that will be, moreboost.org shows -

521rwhp @ 17psi (.68 A/R P trim)
521rwhp @ 18psi (.68 A/R P trim)
533rwhp @ 18psi (.68 A/R GTQ trim)
635rwhp @ 25.5psi (.68 A/R P trim)

I'm going to be running a .68 A/R P trim PT67 myself - I may swap out for Chris' .81 A/R housing, though - we'll see

I fully expect 500 daily driven rear wheel hp - This is a good, safe tune, that I will have no problem running all the time.

I fully expect 675+ race mode rear wheel hp - This will simply add more fuel, as well as the nitrous to supercool the intake temps, and bring the timing back down as well.

I fully expect to hit my goal of 375hp from my build :naughty:

I full expect to be faster than Jeff, at least. :biglaugh:

 

[starscream5000]

Jake, based on that compressor map, the best sweet spot for your turbo will start at about 8psi at 3750 RPMs and still be within it's best efficiency island at 12psi at 6000 RPM's. That's where I would start yourself at right off the bat with your turbo. That thing should be a beast at 12 psi up to +6500 RPMs, but should still be pretty hot on 10 psi and be in the sweet spot the entire time . If I were you, I'd try to get a 10 lb spring for your WG

 

[Doward]

I'd go 12lbs on the spring - just to disagree with starscream there

 

[starscream5000]

Yeah, gotta figure in the pressure drop, maybe a 2 psi drop

 

[Doward]

With Jake's setup, if he's got a 2psi drop in the system, I'll be amazed

 

[starscream5000]

He may want to rethink the 3" IC piping though... Depends on how much boost he actually plans to run though when it's all said and done. Read this Jake: http://www.supramania.com/forums/showthread.php?t=44148

 

[Doward]

I'll be running 2.5" on mine

 

[Reign_Maker]

Ah crap, too much to read...

First I'd like to thank you guys for not making me delete any posts... A slight little sway OT but thats ok... All the information here is very impressive, and well thought out and given with reason and purpose... That's all I asked for, and thats what I got... Thank you guys, I knew I could count on this community...

I've decided I will drop the spring rate... If I decide to run 20psi daily, I can, but if I want to run lower, I can... All this data John is posting is very interesting, especially the moreboost.org stuff... I just wonder how different mine will be... I know I have a 67mm turbo, but isnt the efficiency on it better because its a GT wheel? I also have an 81 AR rear housing... My fuel is, well, over kill I suppose, with 1000cc injectors and a massive A1000 pump... Will this make a difference in the numbers vs. boost? Also, my IC piping will either be full 3" or I may end up doing 2.75" from turbo to IC and 3" from IC to intake... I've got my 3" to intake piping welded up, just trying to source the pipe for the turbo to IC... *should I run 2.75" from turbo to IC?*

Im NOT doing meth injection... I appreciate the suggestion, but like IJ and others have said, I dont want a band aid, and the botom line is, I simply do not trust the meth injection system... If the AEM doesnt turn it on, or the injector is plugged, or it runs out of fluid, or whatever... Too many variables to fail there...

QWIK, thanks for your input, always appreciated...

Screamer, cool link, great post there... I'll have to look more into it later...

 

[QWIKSTRIKE]

No problem Reign...remember no high powered vehice runs race gas on the streets such as lambo's or porsches, or Ferraris. They are tuned out of the factory to run pump. I have a few friends running conservative tunes and getting 600+ RWHP on pump. Reading the Garrett lesson 102, and 103 can hlp you guys understand that richer WOTS is all that is needed up untill a certain point. I never heard of anyone running rich detonating, and that is what you are trying to prevent. Figgie said it best on S/F a while back.....Tune a good tune on 87 octane and then you dont have to worry about bad gas.....an interesting point; However we all want the safest threshold tune towards the agressive as possible. I know that Albert Diaz has a WOT in the 10's with his GT4788 8 second beleve it or not street driven 2JZGTE.

 

[starscream5000]

I've decided I will drop the spring rate... If I decide to run 20psi daily, I can, but if I want to run lower, I can... All this data John is posting is very interesting, especially the moreboost.org stuff... I just wonder how different mine will be... I know I have a 67mm turbo, but isnt the efficiency on it better because its a GT wheel? I also have an 81 AR rear housing... My fuel is, well, over kill I suppose, with 1000cc injectors and a massive A1000 pump... Will this make a difference in the numbers vs. boost? Also, my IC piping will either be full 3" or I may end up doing 2.75" from turbo to IC and 3" from IC to intake... I've got my 3" to intake piping welded up, just trying to source the pipe for the turbo to IC... *should I run 2.75" from turbo to IC?*

Jake, even running 20 psi with the smallest diameter piping being 2.75" and at 6000 RPMs is only going to give you a mean velocity of about 238 ft/sec, well below critical velocity (300ft/sec) which is where you want it to be at in the peak power point on your engine's setup. Honestly, I would go with a 2.5" piping from the turbo to IC, and there to the TB, you will have the best results out of that on 20 psi. At 6000 RPM's mean velocity on 2.5" piping is about ~288 ft/sec., pretty much where you want it. That's why John's using 2.5" in his setup.

Bigger isn't always better

It may be a hassle to you, but you may want to consider changing the piping out to 2.5" to get the most out of your setup.

Edit:: Since you have a .020" over engine, the number are slightly different. 2.75" piping at 6000 RPMs and 20 psi is 242 ft/sec and with 2.5" it is ~293, almost right on the dot

 

[MK3Brent]

2.5" right here...

 

[starscream5000]

Also, you should be loosing only about 1 psi on 2.5 piping from your turbo to the intake mani, but there are other factors to include, but that should be damn close.

 

[QWIKSTRIKE]

Jake, even running 20 psi with the smallest diameter piping being 2.75" and at 6000 RPMs is only going to give you a mean velocity of about 238 ft/sec, well below critical velocity (300ft/sec) which is where you want it to be at in the peak power point on your engine's setup. Honestly, I would go with a 2.5" piping from the turbo to IC, and there to the TB, you will have the best results out of that on 20 psi. At 6000 RPM's mean velocity on 2.5" piping is about ~288 ft/sec., pretty much where you want it. That's why John's using 2.5" in his setup.

Bigger isn't always better

It may be a hassle to you, but you may want to consider changing the piping out to 2.5" to get the most out of your setup.

This would seem to be a good thing to test in the real world rather than in on paper theory....IE on a car with the same turbo and yet different IC pipes. No disrespect intended by this respone. IF you go with a larger pipe and the path way is filled with air volumetricly the larger volume of air is what will yield more efficient power from what I have read. The speed the air travels may be slower but the pathway will have more air molecules. Correct me if I am wrong, so what happens is the response time may or maynot be affected depending on boost pressure. I can only say that in practice going from my stock IC to 2.5 inch turbo to IC and a 3" IC to upper tb run the same configuration as the upper stock IC pipe yeilded me more throttle response. This was with the stock TB at this point. However Going from a 3" to a 4" IC slightly slowed my response time but the shorter FFI routing of pipes eliminated that delay! I think that I can honestly say that in daily practice I'd stay with my 2.5 turbo out and my 3.0" turbo in IC piping. I know that I have the Q45 TB, and an intake that is at least 3.0 liters or a little over it. I put a 2 litre bottle of pespsi over my intake and it dwarfs the pepsi bottle. All that to say that volemtric air is needed more than the speed is needed in order to be efficient. We would need to see the difference in the volumetric air versus the speed the air travels to get a clear understanding of weather a smaller pipe would be more beneficial. It's like travelling on a 2 lane highway or a 5 lane high way. What's going to yield better flow to fill a hot air balloon blowing through a straw, or a garden hose. So far from what I am using no one here can debate with me the fact that on half ass tuning, and all that I have ie. a 2.5" turbo to IC pipe, and a 3.0 " IC to Q45 3.5 " tb reduced to 3.0 IC intake pipe from a 12x24x4" IC, and a 3.0+ litre intake and 22lbs of boost, and piss poor tuning I made 475RWHP, and 450ft lbs of torque with the spark being blown out, and fuel tune issues from the emanage VPC fighting a tps issue.

Respedtfully speaking fro experienced set up

Anthony

 

[starscream5000]

The blowing through balloon with a straw vs. a garden hose is a good example of critical velocity being reached. Let's say instead of the garden hose, let's switch it with a 2" pipe (assuming the balloon will fit around the end) It's going to take you longer to fill up that balloon because you are first filling up the 2" pipe (same with any size).

Depending on the person blowing through the pipe, what their lung capacity is, how strong they are, and how fast they can force air out of their lungs, will also play a factor in this (think of the person as the size of the motor).

What RPM's were you seeing your peak power at with your setup? The best thing to do is have available a set of full 2.5" piping and a full set of 3" piping. Dyno with one, switch to the other, and mix and match if you like. I can't comment on which is best for you as I don't know where you peak power is at, all motors are different and will have peak power in different RPM ranges, especially when highly modified from the stock form like yours was...

 

[QWIKSTRIKE]

The blowing through balloon with a straw vs. a garden hose is a good example of critical velocity being reached. Let's say instead of the garden hose, let's switch it with a 2" pipe (assuming the balloon will fit around the end) It's going to take you longer to fill up that balloon because you are first filling up the 2" pipe (same with any size).

Depending on the person blowing through the pipe, what their lung capacity is, how strong they are, and how fast they can force air out of their lungs, will also play a factor in this (think of the person as the size of the motor).

What RPM's were you seeing your peak power at with your setup? The best thing to do is have available a set of full 2.5" piping and a full set of 3" piping. Dyno with one, switch to the other, and mix and match if you like. I can't comment on which is best for you as I don't know where you peak power is at, all motors are different and will have peak power in different RPM ranges, especially when highly modified from the stock form like yours was...

We definitely agree on the test setup. My peak power was at 6000 rpms but this was with the spark being blown out and really terrible tuning as the afrs were all over the place because my tps setting wasn't functioning on the emanage. I found the wire was broke in the harness. After I install the new Wolf v500 I have sitting on the floor I can give a good test of performance that should be more consistent. The motor has a play in the scenario, but the Turbo is just as much a factor because different size turbos will give different volumetric power out put. Sort of like the large lungs theory only using the turbo as the lungs.:naughty: :biglaugh: I can say that I made 375rwhp by 5000rpms and the power fell then finally went back up by 6k rpms. I can tell you that with the new cams i have made 15 lbs of boost by 4500rpms. What power I am making wont be known until I go redyno.

 

[MK3Brent]

The blowing through balloon with a straw vs. a garden hose is a good example of critical velocity being reached. Let's say instead of the garden hose, let's switch it with a 2" pipe (assuming the balloon will fit around the end) It's going to take you longer to fill up that balloon because you are first filling up the 2" pipe (same with any size).

That is an extremely good analogy.

+1

-B

 

[starscream5000]

We definitely agree on the test setup. My peak power was at 6000 rpms but this was with the spark being blown out and really terrible tuning as the afrs were all over the place because my tps setting wasn't functioning on the emanage. I found the wire was broke in the harness. After I install the new Wolf v500 I have sitting on the floor I can give a good test of performance that should be more consistent. The motor has a play in the scenario, but the Turbo is just as much a factor because different size turbos will give different volumetric power out put. Sort of like the large lungs theory only using the turbo as the lungs.:naughty: :biglaugh: I can say that I made 375rwhp by 5000rpms and the power fell then finally went back up by 6k rpms. I can tell you that with the new cams i have made 15 lbs of boost by 4500rpms. What power I am making wont be known until I go redyno.

Ok, at 22 psi and at 6000 RPMs will net you 624.12466 CFM's. This equates to 211.9 ft/sec on FULL 3" piping with a pressure drop of 0.37 and 305.1 ft/sec on FULL 2.5" piping with a pressure drop of 0.77... You are just a tad over the sweet spot with the 2.5" piping, but then again, with the crappy tune you had on that run I'd hazard a guess and say that your peak power will be higher once you switch to the wolf and get all the bugs worked out .

Let's say you set your redline to 7K RPMs once the wolf is installed. CFM's at 22 psi is 728.14543. 3" piping is 247.2 ft/sec with a pressure drop of 0.50, and on 2.5" it's 355.9 ft/sec with a pressure drop of 1.05... See how fast you loose pressure after you've breached critical velocity?

Edit:: Sorry to thread jack Jake

Once everything's fixed and you're ready to dyno again, if you do it on full 2.5" and peak out there and start running out of steam around 6K RPMs, switch the piping and see if your peak power increases fairly noticably. If it does, then the larger piping is the way to go. I'd say that you shouldn't need anything larger than 2.75" though...

 

[MRSUPRA]

"race gas is still VERY cheap here- 110 for $5.25/gal, 116 for $10/gal....ironic that it doesn't go up nearly as fast as pump gas...."


Now that I think about it, I remeber the local track selling CAM2 110 for $6.00 per gallon. I guess the C16 is following the oil companie trends.

Getting back to the turbo efficiancy topic. There is a guy by the screen name of Blitzsupra on SF. He dyno tested his T61 and then later on changed his turbo to a SP67(same A/R's) and redynoed. With same mods he dynoed:

T61 at 18psi....470rwhp SP67 at 18psi.....470rwhp
T61 at 26.5psi..576rwhp Sp67 at 27psi.....650rwhp

I wish the search function worked on SF so you all don't think I'm pulling these #'s out of my @ss. But I found it very interesting that his smaller T61 made the same power as his SP67 at 18psi. But the SP67 really made a big power difference at 27psi. I know this is not very scientific or mathematical, but it is a real world test that gives us an idea of were a 67mm turbo makes power compared to a smaller 61mm turbo.