Never been to dyno with turbos

...until now. We went to a local dyno today. To get some reference one of the Europes quickest pro stockers having run low 6.7's on European tacks made 1290 hp there. I'm not going to refer any maximum numbers or so because they are kind of useless here since it mademore than we can use and the things re pretty relative anyway.

Our car weighs a bit under 3600 lbs and it has run a best of 7.89/174 mph on DOT tires. It has never really been tuned either chassis or engine wise, and I think it worked pretty good. Now that we put it to the dyno we first got the EFI tuned so that it runs almost like a stock 440 at idle, no fumes and good throttle response. That alone would have been worth the visit.

I took the engine apart during the winter, but theshort block was put together with the same regular moly rings and same bearings etc. Only change was the well served cam to a new slightly different grind and Harlan Sharp rocker arms replacing the well served Ersons. The engine is a 478 RB wedge with a 8.6:1 cr, twin garrets with A/A intercooler, Autronic SM 4 ECU, Weldon fuel pump and regulator etc. etc. The ignition is MSD 7 AL2 and the coil a MSD blaster 2. This is our first turbo build up, and we have run it for three years now, maybe some 50 "passanger" runs, really just driving it without any "program" to try to tune it.

Now today at the dyno we got to fix the cold operation, and now the car starts and runs great without sooting the plugs. It was VERY VERY rich at part throttle, and propably the savings in gas consumption alone will pay for the dyno. We got what we wanted, and proved the things we already knew. The vital theory numbers were very good, but the engine peaked out way lower than we had thought. It really didn't loose much power even above that even though the boost came down and the exhaust pressure came closer and even crossed the boost.

We have wound the engine up to 7500 at the track, the stall with 2/3 SAE 80 trans fluid is about 6200 at full boost and we have shifted at 7100. Well, the engine made peak power at 6100! In the first run the tune up was like it was in the record run and it made 996 hp at 4000 and 1260 hp at 5500. When we had made the adjustments it made 1100 hp at 4000 and 1513 hp at 5500! And that was with 8psi less boost than in the beginning. Should be in time to get some more brewages until the shop closes!

The greates thing in my opinion is that the engine didn't need anything mechanically during the about 10 dyno pulls during the three hours in the dyno.

WOW! you expect to be able to put the new power to the ground with the current suspension?

great job!

We still don't have any electricity to control the power, so getting it to the ground might be a challenge. However, last year we most likely had less tq and power, and since the converter slipped already beyond the peak power rpm (although we don't know what it was with the old cam with abou 10 less intake degrees at .05 and 20 on the exhaust) it wil at least be "soft"

You, without a doubt, have the coolest car on moparts....

Finding 250 HP at the dyno doesn't sound like a wasted day I would think...

Great stuff!

Was far from it. The dyno operator, NOT a mopar guy was happy and the guy that tuned the EFI was happy too, he's very theoretical and he calculated that the engine makes over 100nm torque per litre naturally aspirated which is a good figure.

Do you street drive that animal?

No. It's run in a street car class and is completely street worthy, but because of our traffic legislation and to avoid costs we haven't had the car inspected or insured. The things "wrong" for the registration are too big rear tires, according to the law here you can increase the tire size max 100mm (4") from stock both in diameter and width. And the other one is that the power output of a modified car mustn't be more than 25% above the highest factory offering. Other than that, all the street equipment works etc. Of course we could get it properly licenced and inspected with smaller rear tires and proper dyno papers or even different engine, but have seen no reason to do that. But perhaps someday we will, especially after the tune up nothing prevents the street driving. Earlier the tune up was extremely rich at part throttle and cold starts using a lot of gas and fouling plugs, but now that's corrected too.

Your making some BIG power
What size injectors are you running? 120's?
What fuel?

160 lbs injectors. We used VP109 in the dyno to be safe.

WOW! Very impressive #'s all around. I was impressed when you got that behemeth into the 7's. Good work and thanks for sharing the details.

Amazing! Are you considering a taller rear gear to keep the engine RPMs lower and help tame the traction?

I think we are going to drive with the current converter and rear gear this summer. I made some inquieries about a tighter converter, or more temptating option might be a lock up converter/trans. We really don't need much more speed, already pretty close to having to install double chutes. One problem is, that we have a Dana 60 with 4.10 pro gears, and I have no idea about longer pro gear availability for the Dana.

I dont believe anyone makes a Pro Gear under 4.10 (as far as my research indicated). Like you, I had a 4.10 Pro Gear but switched to a 3.54 but in a street gear, since that is all that is available... but then I will be making about half the power.

Very impressive!!!!

Pretty good results. At what boost level does the car cross the 1:1 pressure ratio threshold? And then what boost do you run at WOT in high gear?

There is a tremendous amount of power left if you can keep the drive pressure on the turbine wheel lower than the intake pressure, or equal.

In regards to the D60 gear setup... we've already been through this. The numerically lowest setup we could find is the Uber rare 3.33 ratio from the LeMans Viper's. Unitrax is a company you can contact to try to source them.

However... the integrity of them is questionable, seeing as they are used parts. In a 3550 lb raceweight vehicle making between 1300WHP and 1700 WHP depending on fuel we had one set last about 45 passes, then the next set last 2 launches. Then the next set lasted 4 launches.

Go figure.

Also, that's good power on VP109... why the unleaded fuel though? European restricitons of some sort, or just easily available? It's rather expensive when C12 will offer better detonation resistance with the lead content.

I guess that only matters if your timing is rather agressive though.

AM

We have run at about 1.5 bar, with that amount the exhaust pressure still stays below the boost. We don't have any electricity to control the boost at the moment, just the throttle. Here are some boost/exh press numbers.
rpm, boost, exh press
4000, 1.44, 0.64
4500, 1.5, 0.72
5000, 1.56, 0.8
5500, 1.57, 0.89
6000, 1.55, 1.02
6500, 1.49, 1.12
7000, 1.38, 1.22
The unleaded is because of the rules. We could also use E85, but no one has really tested the local stuff and I believe it could also test our fuel supply taking it to the edge. Now we have only one Weldon pump there and 160 lb injectors (I think they should be anough for E85 too though). The lambda numbers were around 0.83, so it's still on the safe side.

Quote:

---

It really didn't loose much power even above that even though the boost came down and the exhaust pressure came closer and even crossed the boost.

---

Sorry, because of that statement there I took it that the motor was crossing over 1:1, which by your data it isn't.

That's very good to see, espescially for some guys that claim to not have lots of experience with this type of combo!

If you're looking for an electroinic boost control to aid you, the NLR AMS-1000 works well if triggered off the trans brake button. If you're not allowed to, you could always rig together a series of manual boost controlers with varying settings triggered off of simple solenoids... but that requires driver input during a pass. Probably not the safest deal, ha!