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Hey, I'm the other TT3 Evo in NASA-SE moving to the 71HTA Shaun was talking about. And beware what he says here about surge. Got mine on this past weekend. Here is what happening on 4th gear pulls:
It's doing it some in 3rd gear, but 4th gear is bad. Sounds like an air cannon blowing off rapid fire. Called FP and spoke to Robert after Shaun told me what was going on. Surge is bad enough to stall the MAF readings for a split second (near zero load). Just ordered the flow advancement cover to install. That's a 28psi peak in the graph. The ugly line is 1byte load.
Power Mods:
Stock Block Evo IX
Tomei Poncam R's (270's I think)
MAP Beehive Springs
FUll 3" TBE with test pipe
MAP O2 Housing
Ported Stock Ex Mani
ETS UICP, LICP and 3" Intercooler
ETS Intake
Walbro 255
RCE 720's
Grimmspeed 3-port EBC
Turbosmart WGA (18 Psi)
APS Twin Vent BOV
Dialing down the boost ramp is something Robert also mentioned, instead of the new cover, BUT, I am trying to keep up with the local C5 guys. I want the boost to hit hard and fast, get me on torque asap. So a cover it is.
Good data, I'm going to be using the anti surge cover with mine to try and keep it from surging, and also be taking it a little easy on torque in the midrange to keep the rods happy.
How do you like the Poncam Type R's?? I am strongly considering them but have not found a tremendous amount of user feedback
Good data, I'm going to be using the anti surge cover with mine to try and keep it from surging, and also be taking it a little easy on torque in the midrange to keep the rods happy.
How do you like the Poncam Type R's?? I am strongly considering them but have not found a tremendous amount of user feedback
So far so good. just getting started on getting a tune on the new setup. Even with pretty conservative WG duty cycles (still lots of boost taper) and pig rich it runs strong all the way through 7500. I've put any further tuning on hold pending the new cover. When the load goes from 290-0-290-0-290 during that surging the ECU is grabbing timing and AFR values from all over the place.
On the power vs torque thing. My tune will end up in the 360-365 awhp range. I run NASA TT3 and given the car's current weight, I have to come in at the target power to weight ratio. So I want it pulling hard somewhere between 3500-4000 rpm's (torque), then dropping the torque curve vs RPM's as it climbs to end up right on my PWR number.
And yes you can make that 360-365 on the stock turbo. But doing so (on pump gas) puts you into running the turbo at the edges of it's limits. Doing lap after lap on track, this is what follows:
Last edited by JDavenport; Mar 25, 2015 at 05:32 PM.
Cams should help mitigate surge since the engine can consume more air. My car with the 9 turbo had less surge when I went from stock cams to gsc s2's..
The chances of surging increases when the amount of air an engine can consume increases. It has to do with how much air can be pulled into x size inlet and at y speed. If either the speed of the air or volume of air into the inlet increases the more likely the air is to become unstable as it is pulled into the inlet.
We all know the 71hta is a turbo that spools as fast as a stock unit and flows a great deal more air. As you go up in cam size you increase the volume of air that can be packed into the cylinder which also increases the volume of air that must be pulled through the 64mm opening. At a certain boost pressure, depending on the cams, the volume of air that the cylinders require will over run the speed at which that air can enter the inlet. Speed and volume increase, chances of surge increase.
It seems that a stock cam car that limit at “normal” peak boost is around 25psi, on a mild cam car it’s around 20-22psi, and on a Kel272 or S2 car it’s between 15-17psi.
The reason why your surge issue with the stock turbo was lessened is because the S2's delayed your spool by 250rpm which slowed the rate at which the air was pulled through the inlet enough to keep it stable at the same boost pressure.
I'm glad you're enjoying it so far, I hope the surge cover eliminates all of the surge for you, I think I'll be ok on the surging front but we'll see when we hit the dyno. My goal is to get the car to ramp to around 25-26psi (stock wga and ebcs) and hold it to about 7500 so the car has a really linear powerband. I think a set of cams will help carry the power up top better too. I really would like a car that makes around as much torque as the stock 9 Turbo can in the midrange, but also pulls hard to 7500.
I'm glad you're enjoying it so far, I hope the surge cover eliminates all of the surge for you, I think I'll be ok on the surging front but we'll see when we hit the dyno. My goal is to get the car to ramp to around 25-26psi (stock wga and ebcs) and hold it to about 7500 so the car has a really linear powerband. I think a set of cams will help carry the power up top better too. I really would like a car that makes around as much torque as the stock 9 Turbo can in the midrange, but also pulls hard to 7500.
Well as you can see, the Tomei's open the car up enough that it shows no signs of dropping all the way to 7500 already. As far as spool, I have to get the surge issue sorted before I can lean out the tip-in and do some tuning in that area.
I'll do a max effort pump gas tune once the surge issue is sorted just because I am curious what the setup will make. Then I will dial it down to what I need for TT3. From what I am seeing so far, I suspect the Tomei's and the 71HTA will make for a solid 400/400 pump gas car with a broad fat powerband.
Well as you can see, the Tomei's open the car up enough that it shows no signs of dropping all the way to 7500 already. As far as spool, I have to get the surge issue sorted before I can lean out the tip-in and do some tuning in that area.
I'll do a max effort pump gas tune once the surge issue is sorted just because I am curious what the setup will make. Then I will dial it down to what I need for TT3. From what I am seeing so far, I suspect the Tomei's and the 71HTA will make for a solid 400/400 pump gas car with a broad fat powerband.
Love hearing that! The 71hta and Tomei cams look to be a great TT3 setup as well, all the power you need but running the comp wheel in a place where the turbo isn't heating things up too much. Hopefully you get the surging ironed out soon So you can get to driving!
Well as you can see, the Tomei's open the car up enough that it shows no signs of dropping all the way to 7500 already. As far as spool, I have to get the surge issue sorted before I can lean out the tip-in and do some tuning in that area.
I'll do a max effort pump gas tune once the surge issue is sorted just because I am curious what the setup will make. Then I will dial it down to what I need for TT3. From what I am seeing so far, I suspect the Tomei's and the 71HTA will make for a solid 400/400 pump gas car with a broad fat powerband.
Good info. I have a set of Tomei Procam 11.5mm 270s still waiting to go on with the 71HTA. I'm currently on pump with ~340tq/350whp. Stock WGA, though. Going to wait to switch to E85 until the cams are installed.
Good info. I have a set of Tomei Procam 11.5mm 270s still waiting to go on with the 71HTA. I'm currently on pump with ~340tq/350whp. Stock WGA, though. Going to wait to switch to E85 until the cams are installed.
Those cams will definitely make it scream up top! Tomei makes really good stuff. My plan is to use the new stock WGA that comes with the 71hta, preload it a bit and use that plus my 3 port to hold ~25psi to redline. Hopefully this is possible?
Those cams will definitely make it scream up top! Tomei makes really good stuff. My plan is to use the new stock WGA that comes with the 71hta, preload it a bit and use that plus my 3 port to hold ~25psi to redline. Hopefully this is possible?
Haven't checked thsi thread in a while and just saw this. It should be possible. My setup held 27/28 psi by redline but I was using a Turbosmart WGA with a 22psi spring and a 3 port.
Haven't checked thsi thread in a while and just saw this. It should be possible. My setup held 27/28 psi by redline but I was using a Turbosmart WGA with a 22psi spring and a 3 port.
Yeah I am hoping I can get 25psi at ~7500 out of a new stock IX wga with my 3 port. I just need to figure out how much I need to preload it more or less.
So far so good. just getting started on getting a tune on the new setup. Even with pretty conservative WG duty cycles (still lots of boost taper) and pig rich it runs strong all the way through 7500. I've put any further tuning on hold pending the new cover. When the load goes from 290-0-290-0-290 during that surging the ECU is grabbing timing and AFR values from all over the place.
On the power vs torque thing. My tune will end up in the 360-365 awhp range. I run NASA TT3 and given the car's current weight, I have to come in at the target power to weight ratio. So I want it pulling hard somewhere between 3500-4000 rpm's (torque), then dropping the torque curve vs RPM's as it climbs to end up right on my PWR number.
And yes you can make that 360-365 on the stock turbo. But doing so (on pump gas) puts you into running the turbo at the edges of it's limits. Doing lap after lap on track, this is what follows:
When that happens, you just cut the rest of the volute out, get a new turbine, and put it back together..
Mar 25, 2015, 04:00 PM
