16g not as torquey as t25??

[Gst18]

Hi guys...

First of all i would like to name the mods i have done to the engine...

Stock 7 bolt block
Rebuilt head w/ 3 angle valve job and 1mm oversized valves.
Ported Evo III Big 16g turbo with 34mm flapper.
Ported Exaust Mani.
Ported t25 o2 housing with Custom exhaust dump.
3 inch downpipe
maf-T
24 X 12 X 3 FMIC
RFL BOV
Injen Intake
Stock fuel system.
Im currently running the turbo at 12 psi.

My question is... I had all this stuff done to my car before i put on the 16g turbo and for some reason i would be able to roast them so hard in first and part of second....
My problem is that the upgraded turbo doesnt seem to help the torque.
I can barely roast the same tires in first if i get lucky...

I dont know what could have caused this...

BTW my turbo spools at about 2900-3000 and is at full boost by 3300 Tires are Kuhmo Ecstas on stock gsx wheels.

If u guys have any ideas please let me know.

Thanks

 

[JDNSBR]

First off do a boost leak test to make sure you have none after a change like that.

Second, the t-25 is going to be more effecient on that setup at 12lbs than the 16g. Now if you upgrade your fuel system( injectors, pump, afc or link) and turn up the boost to about 18lbs you will see one hell of a difference.

 

[PieEyedPiper]

1. Do a boost leak test, fix all yoru leaks, and tell us how long you can hold 20psi in your system before your boost gauge bleeds down to 0.
2. Compression test. Warm up the car to FULL operating temp, pull the engine fuse, and unclip the injector plug from the engine. Hold the throttle ALL the way down while cranking.
Report back with your findings.
3. Run a log and post your RPM, TPS, Timing, and O2's.

 

[Gst18]

OK im going to do both tests tonite and let u guys know ASAP!
As far as tunning... I dont have a data logger rite now. Ive been kinda tunning by the feel.
I know thats not a great idea but o well...
My other question was...
were can i find a good write up on how to correctly remove all the emmision crap?

I will be doing the boost leak test and the compretion test.
Thanks guys

 

[diablos991]

There is a saying that goes "Your car never feels as fast as right before you melt a piston."
Morale of that quote: DON'T rely on your butt dyno.

 

[PieEyedPiper]

Search for the taboo information here in the forums, it will tell you all you need to know about emissions and your vaccum hoses.
I suggest you zero out your SAFC/GM MAF if you've been tuning by "feel". Odds are you will run better with stock fuel maps before you can tune with a logger.

~$15 for a palm m105 and hotsync cable off ebay (just gotta find the right deal!)
~$125 for the pocketlogger cable and software

It sounds like a lot, but its worth it. I have that exact combo and I love it.
Better yet though would be to sell your SAFC/GM MAF and save the cash from that and the datalogger and just buy DSMlink.

Glad you're going to run those tests for us, it helps the community help you.

 

[98gst14b]

yea same here I ran a 14b at 18psi with justa 190lph. Then dropped in the b16g and thought It was slowwer than sh@t. I raised the boost to 15 psi and it feels a lot better but the spool is definatly slower . Neways like these guys are tellin ya that turbo is out of its effeciency range at that low of psi. Get some fuel mods and up the boost and youll forget all about your old turbo!! Good Luck

 

[Gst18]

I just got back from running the 2 tests...

Results... i had a small leak coming from my bov. Which im happy i got it fixed now.. Not that it would make a big difference because im running the blow through setup...

Compression test results...

Cyl. 1 (162)
Cyl. 2 (162)
Cyl. 3 (175)
Cyl. 4 (168)

From those numbers i got im glad they are not far apart.

My question is.... Can u guys squeel ## tires all through first and part of 2nd?
I want my car to run as it was low end and also have the high end power i have now. I have to say.... my turbo creeps up slowly to 14 psi in 3rd gear..... AMAZINGGG so much of a difference compared to the t25...

My other question is... Can EGR flow affect any performance? because i had a check engine light go off because of that.

If u guys have any other suggestons please let me know...
THANKS I REALLY APPRECIATE IT!

 

[nightspeed87]

all true about turbo effeciency range, but the t25 supposably doesnt hold full boost all the way till redline therefore would still make the 16g better in all aspects....

 

[MyBeatGSX]

No I can only spin in 1st gear.

The 16G spools rediculously low, the T25 is just a pretend turbo that spools off idle. You can't have off idle boost and make power, so just get used to waiting for your boost until WAAAAAAY up high in the rev range (like 2,500rpm ). Which brings up something to look into. 3,300 is very late for 12psi. I hit 20psi at 2,700-2,800rpm in 3rd weather dependant. Have you checked for pre-turbo exhaust leaks? This could be hurting your spool time and making the turbo feel laggier.

 

[CanadianTSi]

Why do you want to spin the tires anyways

If you are making more HP, which you most likely are, then you ARE making more torque.

 

[nightspeed87]

i say its better to have some off boost time, better gas milage and more trackion to those who have a lot of power, besides if you want a lot of spool up quick just launch from a slightly higher rpm than normal, and if your already moving just downshift into a lower gear..

 

[95talon_in_ma]

Just a guess, but since your boost pressure seems really odd to not hit full boost until 3k, perhaps it's the wastegate.
Found a good thread that talks about the 34mm mod you have. Maybe move to an external?
http://www.dsmtuners.com/forums/showthread.php?t=163103

If that flapper area has a crack, it might only show up after the car was running and hot. If you did a leakdown test when it was cold, it might not have shown up.

Also, More HP does not necessarily mean More torque throughout the rpm range. Especially Peak.
Here ia a good thread that has a dyno graph that illustrates this point.
You will notice they saccraficed approx 60ftlbs in the lower range of torque for a gain of 50HP at 5600 rpm. The torque curve is broader, but definitely less at lower rpms. Granted this is strictly for an intake but the same rule applies.
Yes there is more torque when there is more hp since hp is a calculation of torque and engine speed, but not as a whole.
My own opinion is to decide where the car will see most of it's driving. If you do alot of racing and allot of 6000 rpm shifts, then it's worth the sacrafice, but light to light I'd go for the torque.
Not that the 16g can't do it in lower rpm's, you just need the fuel mods and maybe an external wastegate and run it around 18psi to get it there.
http://www.dsmtuners.com/forums/showthread.php?t=224551

Duane

 

[MyBeatGSX]

Please don't start a HP vs Torque war. Horsepower makes the car go, plain and simple, end of story. And for future reference, the word "torque" is not interchangable with "low end power". Torque is torque, whether you make it high or low. If you are making more power, then you are making more torque. Unless you increased your rev limiter, which he didn't do.

If he can't handle the spool time of a 16G, then he needs to get out of turbo cars. Go buy an F-Body.

 

[quattro527]

Please don't start a HP vs Torque war. Horsepower makes the car go, plain and simple, end of story. And for future reference, the word "torque" is not interchangable with "low end power". Torque is torque, whether you make it high or low. If you are making more power, then you are making more torque. Unless you increased your rev limiter, which he didn't do.

If he can't handle the spool time of a 16G, then he needs to get out of turbo cars. Go buy an F-Body.

Second that.

Coming from a MKIV Supra, with big turbos that dont spool until 5000 at times, the lag on the big EvoIII 16G feels like nothing.

 

[95talon_in_ma]

Please don't start a HP vs Torque war. Horsepower makes the car go, plain and simple, end of story. And for future reference, the word "torque" is not interchangable with "low end power". Torque is torque, whether you make it high or low. If you are making more power, then you are making more torque. Unless you increased your rev limiter, which he didn't do.

If he can't handle the spool time of a 16G, then he needs to get out of turbo cars. Go buy an F-Body.

Wasn't trying to dive into the "war" of HP vs Tq. (didn't know there was one) I agreed with you that if you make more HP you will make more Tq at that same point since they are directly related .
HP = (Tq *RPM)/ 5252
I too agree with you that Torque is not interchangable with Low end power. I apologize if it sounded like that is what I was saying. I just meant that, specifically in the graph I linked to, changing that part increased the upper RPM HP (and Tq), but they lost HP (and TQ) in the lower RPM's.
In general I was trying to say that all power adders have a trade off. Whether it's reliability, driveablity, gas mileage, or simply moving the power band so you can't roast your tires anymore, it's a trade off.

As far as upgrading the turbo specifically, you guys are all over me on that. I wouldn't even pretend to speak as to how it should or shouldn't be. Just a guess as I noted...

sorry for the confusion..

 

[tneclipsegst]

so i never saw anyone answer the tires squeeling question so i guess i be example. i have a forced performance big 16g turbo in my gst. i have the fuel mods everyone rightly suggested. the tires squeel likes crazy. i guess its all in the setup. i like my 16g it spools pretty quick, hold max boost throughout rpm range (or at least until redline dont go past it EVER), and will put me in my seat.

 

[Turbocharged]

Horsepower makes the car go, plain and simple, end of story.

Torque makes your car go, horsepower keeps it going. The reason you want flat torque is so that your horsepower continues to increase linearly with rpms. Torque is basically the rate at which your horsepower changes.

http://www.castlerockacres.com/Dyno-RPM.jpg

 

[quattro527]

You will break traction much easier with the T25 vs a bigger turbo, for the ramp up comes in much sooner at the powerband, in a range where the car is still working hard to pick up momentum. The 16G will ramp up in a range where the car has already picked up that momemtum, and it will take much more torque to break them loose at that RPM.

 

[VicBoost]

First off upgrade your stock fuel system!!! Only 12 psi on the 16g what you expect. Get the walboro 195 or 255 and then get bigger injectors probably 650 or 550.

 

[VtecvrsTurbo]

Take a look at my dyno graph. Try having no lsd and 215 pounds of torque around 2500rpm. I hate that. It makes launching a joke. I wish i didnt have that much low end torque, mabye I could go somewhere. P.s. Why would you want to squeal the tires anyways? Rev it to 7000 in second gear and see if it squeals. You DONT want it when your launching. WTF

 

[NewTurboTuner]

Spinning tires does not mean you are fast or slow. It just mean you make power down low. My F250 Turbo Diesel has over 500lbtq at 1800RPM, and can spin the 35" tires with no problem... but with only 260hp up top... the power falls of quick and the truck dosent acelerate fast.

Just because you are spinning tires before, and not spinning tires now... that dosent mean you make less HP. Plus if you are spinning tires then you're not excelerating as fast as you could be. Its just a waste of power if you cannot put it to the ground. You might as well not have that power if you cant use it. A fast car needs HP high into the RPM's. Thats where it really counts if you want to go fast. With a front wheel drive car its actually better to have boost kick in a little later... that way the car is already moving before the big boost kicks in, and you'll get better traction that way.

I bet the car is faster, but since the power is more smooth, the butt-O-Meter dosent measure it as good.

....Hopefully that helps to expalin a little

later!

 

[JayRolla]

Which brings up something to look into. 3,300 is very late for 12psi. I hit 20psi at 2,700-2,800rpm in 3rd weather dependant. Have you checked for pre-turbo exhaust leaks?

Damn 20psi before 3000 rpm's. I have like 4 friends all with 16g's and they hit 20psi between 3000-4000rpm's depending on the set up. I dont hit my full 11psi untill about 3200rpm's. So there is something wrong with our cars or what becuase I wish my turbo spooled that fast.

 

[nightspeed87]

Spinning tires does not mean you are fast or slow. It just mean you make power down low. My F250 Turbo Diesel has over 500lbtq at 1800RPM, and can spin the 35" tires with no problem... but with only 260hp up top... the power falls of quick and the truck dosent acelerate fast.

Just because you are spinning tires before, and not spinning tires now... that dosent mean you make less HP. Plus if you are spinning tires then you're not excelerating as fast as you could be. Its just a waste of power if you cannot put it to the ground. You might as well not have that power if you cant use it. A fast car needs HP high into the RPM's. Thats where it really counts if you want to go fast. With a front wheel drive car its actually better to have boost kick in a little later... that way the car is already moving before the big boost kicks in, and you'll get better traction that way.

I bet the car is faster, but since the power is more smooth, the butt-O-Meter dosent measure it as good.

....Hopefully that helps to expalin a little

later!

Kind of what I was trying to say, and in my opinion yea if I was awd and was only worried about 60ft and 1/8 mile times then yea i would want a stronger lower powerband, but for all out top end racing and nothing shorter than a 1/4 then I would want the power up high... Spinning tires just stresses other compenents for no reason because its not going anywhere, thats why a lot of srt4 guys have mad power but dont get good times, because there 2.4s and torque happy and cant ever get traction once modifyed, so sometimes modfying them could be making them slower because there having trouble getting the power to the ground...

here this might help some of the technical people
http://www.revsearch.com/dynamometer/torque_vs_horsepower.html

 

[MyBeatGSX]

Torque makes your car go, horsepower keeps it going. The reason you want flat torque is so that your horsepower continues to increase linearly with rpms. Torque is basically the rate at which your horsepower changes.

http://www.castlerockacres.com/Dyno-RPM.jpg

PUH LEZ bro... you sound like a car salesman.

Torque and HP are 2 different ways to measure the same thing. Like measuring water in pounds or gallons. Water is water no matter what way you express how much you have.

A 300hp car is a 300hp car, regardless of how much peak torque it makes. If its a Civic it might make only 200lb/ft high up. If its a Mustang it might make 350lb/ft off idle. Either way its a 300hp car. At higher RPMs the Mustang starts to fall on its face, and at lower RPMs the Civic can't get moving. Make both cars the same weight, gear them so that they take advantage of their respective powerbands (which they will be from the factory in most cases), and go at it on the highway. They'll pull the same.

People get too caught up in crank torque numbers, ACTUAL wheel torque is what matters and dynos don't show you this. You have to remember that the Civic has some very high (numerically) gear ratios that will give it almost the same torque at the wheels as the Mustang. And the Mustang has some low (numerically) gear ratios to make up for the fact that it can't rev and can't always be destorying its tires. The only difference between the 2 cars is the HP they will put out at a given RPM. HP does not get converted when put through gear ratios. So that Mustang that makes more torque at a low RPM will have more HP to put to the ground at low RPM. The Civic makes very little torque at low RPM and so has very little HP at low RPM. This makes the difference in acceleration. The actual torque at the wheels is identical for all intents and purposes. I spared you and myself the math, so just trust me on this one.

A torque curve shows the actual force of the engine at a given speed. You look at this when you're tuning.

A horsepower curve is just a simplified translation that shows how much work can be accomplished with that force. You look at this when you want to see how the car will accelerate.

Torque is torque.

Horsepower is horsepower.

They are two COMPLETELY different units of measure, used to measure the same thing. Just think a pound of water or a gallon of water. The water is still just water. I've never heard anyone ask the difference between a gallon and a pound. Just try to think of how you would explain that.

10lbs of feathers weighs just as much as 10lbs of lead. That has no relation to anything I just said, but it should help you understand the overall concept.

I hope that puts it to rest.




Back on topic...

Jay,

What gear are you guys making these pulls in? I'm in 3rd. How hot is it outside? What size is your downpipe and what kind of O2 housing are you and your friends running?

I have an Evo III exhaust manifold, tubular O2, 3" catless DP, and metal intake pipe. Each of these made a very big difference in bringing the full boost RPM down to where it is now. My turbo is also brand new, I'm sure that helps. I have no boost leaks and no pre turbo exhaust leaks.

If you have a similar hot side setup and are taking until 3,200rpm to hit 11psi in 3rd gear, there is definately something wrong with your car. Keep in mind, heat and especially humidity (the turbo has to pump water) have a significant effect on spool time.