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This morning I realized that TurboXS is only a couple of miles from where I work and I've been looking for a dyno, so I called them up. It was my lucky day... they are pretty much booked up for dyno runs until July, but someone cancelled today and they were able to take me in right away. I didn't have a chance to go home and install my race pipe, but with my new Greddy e-01 EBC I wanted to make sure I wasn't overboosting so I decided to take the slot anyway to check the A/F ratio.

I met Nathan and Phil at TXS, and they were both very cool. They hooked me up, and with 17 psi boost I got over 260 HP! They were even surprised, because up to that point they haven't been able to get that much power from their project car either.

It turns out that the way I have the EBC connected, T-eed into the existing compressor outlet vacuum hose port, is a big deal. Apparently, the car's stock boost solenoid needs to see pressure, or else the ECU compensates and all you get is more torque, not HP. (I might have the technical explanation wrong, but I'm sure Nathan can correct me if I'm wrong.) After I left, they hooked up a boost controller to their bone stock SRT-4 the same way, gave it 17 lbs of boost and got the same numbers, or close to the same numbers, as I did.

The A/F chart shows that the car starts to go lean at around 4800 RPM, ending up around 12.0. They said that showed I was running out of fuel due to the small stock injectors. But we didn't hear any detonation and they thought it was fine. For the street they advised that I should keep the boost around or under 16.5 psi.

So the good news is great numbers! The bad news is that compared to their car, my ATP Stage I downpipe+cat didn't seem to make much of a difference. But they've squeezed me in again next Saturday, the 26th, for another set of runs, this time with my racepipe installed.

I spent some time talking to Nathan and Phil afterwards, and asked them about their plans for the SRT-4. They will be coming out with lots of stuff, including their UTEC engine management system and a bigger Garrett turbo, in around 6 months. They demo'd the UTEC for me. That thing is awesome. I'm definitely getting one! They think they can get the SRT-4 up to around 400 HP.

Here are my charts. The high numbers are mine. The low ones are the baseline for their project car.

It was around 50 degrees, 60 % humidity. They did spray the FMIC with water before each run. They did use a fan. The numbers are actual HP, not SAE corrected. My mods include:

ATP Downpipe
ATP Hiflow Cat
Greddy Profec e-01 EBC
DR Motor Mounts
PVO-style "Hood Mod"
K&N Drop-in Air Filter
ATP UPP + HKS BOV
Blitz DTT-DCCII Turbo Timer

HP vs Torque:
http://import.h8rs.com/drolander/TurboXS_SRT4_Dan_HP.PNG

A/F Ratio:
http://import.h8rs.com/drolander/TurboXS_Dyno_Dan_SRT4_AFR.PNG

Boost:
http://import.h8rs.com/drolander/TurboXS_Dyno_Dan_SRT4_Boost.PNG
 

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I see what your saying, but this makes no sense that the BCS (boost solenoid) would NEED to be connected. If you look at the way the BCS works, it's a ON/OFF type device that bleads to the atmosphere. There is no way that I can see, the ECU knowing it's got pressure. It would have to have some of MAP sensor in it, which we know it doesnt.

Can you please explain your logic ?
 

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One other item. I believe I originally had mine setup the same way. It worked great for two weeks, then I noticed that the boost level started to drop. I unhooked the MBC and ran it stock immediately after. It would not boost higher than 8psi! I reset the computer and it went back to the original 12psi. This indicates that the computer eventually was trying to correct for the difference in boost that the MBC was making...

-Sam
 

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Since no one else has said it yet, very impressive numbers Dro!

If you factor in 15% drivetrain loss, you have a little over 300HP! :shock:

Oops, I just saw that the results are flywheel ratings. :oops:
 

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AWD_ENVY said:
I see what your saying, but this makes no sense that the BCS (boost solenoid) would NEED to be connected. If you look at the way the BCS works, it's a ON/OFF type device that bleads to the atmosphere. There is no way that I can see, the ECU knowing it's got pressure. It would have to have some of MAP sensor in it, which we know it doesnt.

Can you please explain your logic ?

It's looking for a switching feedback not a control feedback. I'll explain more at a later date. This might be a difference due to a different version of the ECU programming (mine was last updated in March) so I want to investigate it a bit more on a few different cars.

Bottom line is that up until today we were making stock HP with 16psi of boost. It would make more torque down low, but up top the car would dump fuel.

With the factory line left on the compressor cover and the waste gate return plugged, we managed to make an additional 35hp and 36ft/lbs. This modification would cost you $129.

You must T off of one of the lines on the manifold for your MBC pressure source or the car dumps tons of fuel and pulls the ignition timing way back. I wasn't quite ready to release this information just yet on the boards because I need to do some further testing on a few more SRT-4s before we can make any broad statements.

In any case after a week of testing all the different combinations, I am happy with the results. Also, as a side note, preliminary testing on upgrading the BOV and using a block off plate on the stock unit is showing around 2psi of pressure gain at redline.
 

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nmyeti said:
With the factory line left on the compressor cover and the waste gate return plugged, we managed to make an additional 35hp and 36ft/lbs. This modification would cost you $129.
Let's see, 35HP for $129, where do I sign up?
 

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RUgoinup said:
Since no one else has said it yet, very impressive numbers Dro!



Oops, I just saw that the results are flywheel ratings. :oops:


Note the TCF on his dyno plots. When TCF is set to 1 the hp recorded is actual HP produced at the wheels, or more correctly HUBS since you unbolt the wheels and run the hubs on each dynapack. If I were to set the tcf to 1.15 it would add 15% and he would have closer to a true flywheel number.

He is making an actual 30whp more than a stock car on our dyno.
 

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I was looking into this my self. I notice that if the the stock solenoid does not see any boost, you will get a P1188 fault code even if you have it set at 13psi! And no its not an overboost code which is p0325 if i recall (saw that one too :) )

I found this to be odd. I checked for voltage at the boost solenoid and it reads alternator power which I found it to be more of just an open close switch type solenoid.

So my question is, how does the ECU know if the stock solenoid is seeing boost or not? My current guess is that its an electronicly controlled switch, but maybe musle air activated. In other words, the voltage allws the switch to unlock, but the boost pressure probly moves the switch open and causes a change in resistance that the ECU might see.

Things that make you say hmm?


Good numbers by the way Dan!
 

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Im lost here.....I was about to say holy shit batman, but the graph shows flywheel HP.

Is it flywheel? or is it at the wheels?

Never mind...I re-read nathans post.

Now I can say it...HOLY SHIT BATMAN!!!

Sucks that they got the same gains with their stock setup, showing ATP's stuff was useless?

Cali
 

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nmyeti said:
cali said:
Im lost here.....I was about to say holy shit batman, but the graph shows flywheel HP.

Is it flywheel? or is it at the wheels?
Read my response above. It's at the wheels and 30hp over our stock car at that.

-Nathan
www.turboxs.com
I re- read it before you posted...sorry :oops:

Another thing is ....this completely explains my cars problems.... can wait for a new #3 solenoid :)
 

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Discussion Starter #15
I don't want to say that the ATP downpipe is "worthless". Before I started boosting, my "butt dyno" measured a significant gain from it, at least in low end torque. I haven't seen Nathan's new charts, just heard about them, so I can't compare them to mine. I'll ask to see them next week. At any case, the big 3" DP and highflow cat *has* to be better than stock.

We tried reverting to the stock boost controller to compare my car with DP to their car without, but we were only able to get 8 psi. At the time, we thought it was because the only line we moved was the one to the wastegate, and we left the rest of the lines to the new EBC in place. But this is interesting now considering Sam's comments. So anyway, we weren't able to determine what the DP is adding. But I will be able to figure out what the racepipe adds on the 26th.

Dan R.
 

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drolander said:
We tried reverting to the stock boost controller to compare my car with DP to their car without, but we were only able to get 8 psi.
Dan R.
Yup, exactly Sam's scenario.
Good findings, and I hope it gets better for all of us!
 

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drolander said:
I don't want to say that the ATP downpipe is "worthless". Before I started boosting, my "butt dyno" measured a significant gain from it, at least in low end torque. I haven't seen Nathan's new charts, just heard about them, so I can't compare them to mine.
Dan R.




Dan,
You have a tiny bit more torque from 3500 to about 4900 than our test car. I'll overlay the plots and try to have Phil send them to you this weekend.

There are 2 things that could be happening here.

1. We have a strong car (i suspect this is true)
2. The main restriction is behind the cat (i also suspect this is true).

Some friends of mine have measured 11psi of backpressure in the stock exhaust system. I think most of it is from the cat back, but we'll know more as our testing progresses. Once you replace the main restriction in the exhaust system I think you’ll end up uncorking a whole lot more power over a car with just a boost controller.

By the way, I am pulling the HPBC back out of the car in the morning. I think this car must have a duel stage controller because at high boost I just cook 1st through 3rd in the weather we are having down here. Now I just have to get my slicks and head to the track. I can’t wait to put a big turbo on the car!
 

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Nathan, you aint lying when you say it needs a dual setup. Even down here in FL with the warm weather, the tires break to easy. YOu definatly need less boost in 1 and 2 gear. If your peeling 3rd up there then this is pretty wild. Im have my e01 set to a low boost. I have the scramble boost set for 3rd gear and up.


Have you ran into any p1188 codes? I dont have a cel but I see it as a pending code depending on what source I hook up my ebc.

I am using the line coming off the manifold that supplies the brake booster as my pressure source for the EBC. I replaces the stock vacuum joiner with a T. After a couple of days of driving like that, the T melted do tue the water line for the turbo that is there. For those who plan on using this source, make sure you poing the T down so you dont melt the tip off.
 

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I sure would like to know if I got screwed by buying the ATP stage 1 cat/dp kit, there charts show a 15hp/40lbft increase, I am not expecting miracles, but I am going to be pissed if its a 3hp/10lbft difference.
 
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