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I went to a dyno to see how much power the engine is making. I have had this car for over twenty years and made several dyno pulls. The car feels faster than ever. The hp numbers are the lowest ever. :-)
In the past I was running a Super 48 turbo @ 18 psi boost. Now I'm running a Raptor turbo @ 14.5 psi boost. In the run the boost dropped a bit after 5000 rpm because of an issue controlling the boost with the EBC. Increasing the boost solenoid duty cycle increases the boost well above 15 psi. I have ordered a set of wastegate springs to find the spring best suited for my application. I expect to gain a few hp at the top when I get the boost to stay steady at 14.5 psi. Nevertheless, the car drives amazing and is very quick.
Nice! Initially I only looked at the first plot and thought it was strange that the curves didn't cross at 5250. But then the second plot they do. Interesting.
Nice! Initially I only looked at the first plot and thought it was strange that the curves didn't cross at 5250. But then the second plot they do. Interesting.
HP = T(RPM)/5250
HP = T @ 5250 rpm.
Thanks
Mike G.
That puzzled me as well. Will ask the dyno guy why the lines do not cross at the expected point.
Nice! Initially I only looked at the first plot and thought it was strange that the curves didn't cross at 5250. But then the second plot they do. Interesting.
HP = T(RPM)/5250
HP = T @ 5250 rpm.
Thanks
Mike G.
Not that hard! The y-axis are different.
HP on the left axis, Torque on the right.
Because chart one and two have different scales they don't match the crossing at 5252 rpm. That the lines did cross near 5252 rpm on the one chart is by coincidence.
Because chart one and two have different scales they don't match the crossing at 5252 rpm. That the lines did cross near 5252 rpm on the one chart is by coincidence.
Happy 4th of July!
Not only that but the units look to be in Metric for Torque, Nm and SAE HP = PK? Funny that the one graph actually crosses at the magic 5252. Cause and causality?? haha
Thinking about it a little bit more it would be nice to have the same scale for HP and T as it gives you a data point at 5252 that a least verifies that something is correct.
Mike G.
Last edited by Mike Goebel; 07-04-2022 at 07:38 PM.
I have a question or two...I've had cars on dynos before, but when I had my old 951 on a dyno, it only spun the rollers that the rears were on. The dyno you are on is also rolling the fronts. So if the front rollers are connected to the rears, wouldn't that account for the "less than butt dyno" numbers you got or is that dyno calibrated to offset because of both rollers spinning?
I have a question or two...I've had cars on dynos before, but when I had my old 951 on a dyno, it only spun the rollers that the rears were on. The dyno you are on is also rolling the fronts. So if the front rollers are connected to the rears, wouldn't that account for the "less than butt dyno" numbers you got or is that dyno calibrated to offset because of both rollers spinning?
I can't imagine that the numbers would be less due to the type of dyno. The dyno is calibrated. It measures the torque the wheels put on the rollers (at the rear axle) and calculates the hp.
I'm not to worried about the numbers. I have set a baseline and will go back to the same dyno after a few tweaks to the boost mapping.
Keep in mind: I'm running only 14.5 psi (and less after appr. 5000 rpm).
Almost 10.000 km (6213 miles) on the new engine. I have a minor issue with the wastegate. In fourth gear at around 4500 rpm the boost pressure becomes wobbly. Sometimes it reaches the overboost limit and gives me a fuel cut (which is not a big deal). Would like to have a rock solid boost "curve" and I was discussing my issue with someone. He pointed out a website where you can calculate the required wastegate size for a specific engine with a certain amount of power. Het calculated for me that I should use a (at least) 45mm large wastegate. At the moment I'm using the Tial 38 (mm) wastegate. I the calculations are correct, I might need to go for a Tial 46 mm.
What also might be causing the problem is the exhaust setup. Stock, the wastegate dumps the are after the catalytical converter. I am not required the use the cat on my car and have a 3" exhaust (with a 3" downpipe). After the point where the wastegate exhaust pipe connects to the main exhaust I have placed a (see through) muffler.
Can someone confirm that the Tial 38 wastegate might be too small for 300 whp?
Or should I start by removing the muffler and see if that might solve my "issue"?
Almost 10.000 km (6213 miles) on the new engine. I have a minor issue with the wastegate. In fourth gear at around 4500 rpm the boost pressure becomes wobbly. Sometimes it reaches the overboost limit and gives me a fuel cut (which is not a big deal). Would like to have a rock solid boost "curve" and I was discussing my issue with someone. He pointed out a website where you can calculate the required wastegate size for a specific engine with a certain amount of power. Het calculated for me that I should use a (at least) 45mm large wastegate. At the moment I'm using the Tial 38 (mm) wastegate. I the calculations are correct, I might need to go for a Tial 46 mm.
What also might be causing the problem is the exhaust setup. Stock, the wastegate dumps the are after the catalytical converter. I am not required the use the cat on my car and have a 3" exhaust (with a 3" downpipe). After the point where the wastegate exhaust pipe connects to the main exhaust I have placed a (see through) muffler.
Can someone confirm that the Tial 38 wastegate might be too small for 300 whp?
Or should I start by removing the muffler and see if that might solve my "issue"?
What are you using for a boost controller? Manual or electronic? The lack of boost control can have many causes? Wastegate spring? leaking lines to/from the controller, exhaust leaks?
I have an electronic boost controller which is controlled by my AugTronic ECU. Boost control is spot on up to 4500 rpm and after that becomes less spot on.
It has been some time, but I finally have an update.
Below is the fuel map which delivered me a (nearly) spot on AFR. Fuel map
The part marked by the red box has always puzzled me. Why do I need more fuel around 4000 rpm than above 4500 rpm?
However, the AFR was good, the power was also good.
I had replaced the stock fuel rail with the Lindsey Racing billet fuel rail. The LR fuel rail came with a fuel pressure damper at the back of the fuel rail (near the firewall). The damper was big and made a hell of a knocking sound. I replaced the (Marren) fuel pressure damper with a Radium fuel pressure damper which was placed at the right shock mount. The Radium damper reduced the knocking sound a lot. However, the knocking was still noticeable while idling.
Somewhere I read that a fuel pressure damper should be placed before the fuel rail. I rerouted the fuel hoses and the knocking was again reduced.
When I wend for a drive I noticed the turbo was not building boost. I hooked up the laptop and started adjusting the duty cycle for the boost controller. Normally 31% resulted in 15 psi. At some point the duty cycle was 35% and the turbo still wasn't building boost properly. Normally I test in third gear. Because I was puzzled about the boost issue I wanted to try a pull in second gear. Around 3000 rpm the boost was better, but still not good and than I hit 4500 rpm...
The car was pulling like crazy and around 5000 rpm I heard a sound coming from the back you don't want to hear. At first I thought it was an exhaust part that came loose, but sadly that was not the case. I broke my transmission! I clearly put too much power on the transmission which probably resulted in a broken ring & pinion.
An analysis of the log files showed me that (after repositioning fuel pressure damper) the AFR was way off in the rpm range marked in the picture above. I think I will have to take out a lot of fuel in that rpm range.
On Friday I will bring the transmission to the shop who rebuild and modify my transmission 7000 miles ago.
If the R&P is in deed in need of a replacement I think I will have them put in the R&P from a S2 transmission.
As soon as the transmission is back under the car I can figure out if the fuel map has to be adjusted as suspected.
07-03-2022, 06:57 PM
