New run for triple t 928 1984 4.7

[sonett3]

We have over 400 wrhp as of 01/19/07 with 2.19 psi more.

[Herr-Kuhn]

You need to give them more specifics...like:

My brother was generous enough to donate parts of his left over Callaway TT system and an entire 4.7 liter M28.12 engine for this project...

Since I built this engine I can give some of the specifics....it is a twin turbo 1984 4.7 liter. US cams and intake on top of an 82 Euro bottom end/heads. Nikasil plated bores and JE 2618 pistons to my design specs to yield 8.1:1 static.

The dyno results are pretty impressive, specifically considering this car has the old-skool Callaway manifolds and circa 1979 IHI turbos...we even put the small hotsides on this car to help the spool out some. The larger hotsides would open up about 15-30 RWHP. MAF conversion and Intercooling are my design. It is a hybrid of sorts and was built on a budget.

Torque is over 450 ft-lbs at the tire at 4,200 RPM. RWHP is 380-400 from about 4,500 to 5,600+/- RPM. There is a nice wide powerband...over 300 RWHP by 3,800 RPM...a full stock Euro 4.7 liter only makes 300 crank HP at the top end...and that is with the good cams and intake! These are straight, uncorrected numbers. Dyno correction factors can skew numbers in either direction.

I have yet to see a boosted 4.7 liter make these kind of numbers. With better cams and modern turbos I have little doubt this car could get well north of 450 RWHP. What is most impressive is the wide-punch powerband that turbocharging delivers to the 928. Proof again that turbos can, do, and have been working on the Porsche 928 since the early 1980s.

Riding the Triple-T is like being launched out of a sling shot...it is a wicked ride for sure...especially when you consider this car would have probably ended up in a scrapyard based on its condition 2 years ago. The previous owner was not so kind to the car.

Dyno sheet is a .pdf. I'll have to see if I can get it converted to a .jpg or do a rescan so it can be put up here.

He has more HP than me for now....but that will be changing next month when I unleash the 32V TT. It should be like a Pitbull on steroids. I have to keep pushing the bar

[Danglerb]

Don't forget when increasing the BAR that a VPR is also called a variable piston remover.

Nice work. I am especially following the MAF conversion.

[Herr-Kuhn]

Thanks for the positive feedback...and for those who want to contribute to this discussion...it would be best to do so here, rather than to drag the information to other boards. This is a good place to share and discuss technical information.

This place can use some more people, I hope it ends up getting more popular as time marches on.

[Herr-Kuhn]

Some photos of this rebel of a car...I'll get the dyno sheet converted to .jpg format this week.













LONG LIVE THE TRIPLE-T!

[Fabio421]

Why did you replace the bottom end of the engine? And why did you use a Euro bottom end? Isn't the only difference between ROW spec and Euro spec 4.7L bottom ends the compression ratio's?

[Herr-Kuhn]

Forged Pistons were the reason for the rebuild. The Euro bottom end was one I had as a spare...it was a known entity, while the old Callaway block was sleeved 2X and it had issues because of past abuse and bad wrenching. The forged units give a lot more strength...it is substantial.

This now has a cr of 8.1:1...stock is just about 10:1.

Good to see you over here...I think you will find more people giving this forum a chance. If you want to see and talk about my stuff it looks like you will have to come here to do so. It is great...today's "activities" just bring more people over to Pelican and to this board in particular.

You want to see results...just wait about 3-4 more weeks!!!!

[Herr-Kuhn]

This .jpg might be tough to read but I though it was only fair to put the dyno results up here. Considering this car is breathing through a US topside and camshafts the results are nothing short of a true win.

This is a classical turbo car power and torque curve. A turbocharged car will almost always peak off before its normally aspirated counterpart...that is just the way it works. For some reason people assume a car that doesn't peak at redline is not fast or is lacking. Not so, this is a potent ride and for a street car the power curve is really nice.

All normally aspirated 16V 928s roll off on power up on the top side...specifically the US cars because of the camshafts. The 84 cams are not the best...he has a set of 79 units we will install at a later date...should hold the power another 300-400 rpm. Also, when I consider this thing is using the old RHB-6...with an even smaller hotside than I used on my 4.5...it makes the numbers even nicer to see on the sheets. What is most impressive to me is how she rolls on hard in the mid range and holds 380-400 HP to the wheel over a large rpm range. For lack of a better term, these turbos are junk by today's standards of performance. It is old skool all the way. However, it is hard to argue with 450 + ft-lbs to the tire on an old 1984 928. I have to say, Mark did a great job of dialing this car in down in Florida. Several people went to purchase this car and left it for junkyard material. It was really rough when it came down to Florida (and when it came to KY for its new heart and lungs)

The dyno was an eddy current unit where they were able to fully load and hold to dial things in. Numbers are not corrected. Additionally, eddy current units typically give lower numbers than a dynojet.

I figure this motor NA would make about 265 crank HP or so

Guys...if you all have something to say (for those who are not banned that is , just say it on here. I don't post here to have my work show up on other places (trust me that isn't a goal nor will it be). This is a good board with good people and I hope it stays that way.

[MENACE]

How much would it cost to get forged pistons done on a 928. The reason I ask is because I have a 16v euro '82 S, I plan on getting a 928TS 16v kit but want to run higher than average boost so I guess I need a better CR.

[Danglerb]

If they are the ones I am thinking of, its about $1400 a set I think. Personally I am not ready to try a non Porsche piston yet, not that others don't seem to have them working, its just a short track record with few examples.

[Herr-Kuhn]

This all depends on how you want to build the bottom end. A nice upgrade is to do a JE2618 piston set and Nikasil plate the block. This way you get new walls, pistons, rings, and pins. Plus the Goetze ring packs from the 911 series can be used. I've built 3 engines with this combo and thay have all ended up working very well. The triple-T is of these configs as is my 4.5 liter 1981. The 4.5 has over 10,000 miles on the rebuild with no issues.

On the 16V engines without knock control, I recommend around 8:1 or maybe up to 8.3:1 or so.

Should you be interested I can build a bottom end for you to these specs...you would just bolt on the heads and accessories and go. I already have the 4.7 liter Euro piston set numbers through JE...it would simply be a reorder. TTT runs 8.1:1 CR and this seems to work pretty well.

One of the weakest features on the 16V engines is the top ring land. On the 32V engines the top ring land is about 50% thicker than on the 16V examples, thus it can handle more abuse...plus that car has knock control and can pull out 9 degrees of timing.

Send me a message if you want to talk over what is involved with this type of rebuild.

[sonett3]

Tripel t is going back on the dyno again this friday 02/02/07.

[Fabio421]

What piggy back system are you using in the TTT that allows for laptop tuning and adds knock control?

[Herr-Kuhn]

Fabio...this is the Split Second PSC1-009 system with a draw through MAF sensor. There are a few tricks to make it work, but as you can see, it does indeed work. The throttle response is really nice with the MAF conversion...much snappier.

[sonett3]

Going back on the dyno tomorrow. I hope to get 430rwhp that would put it at480 to 490 at the fly wheel or so.

[john928]

"These are straight, uncorrected numbers. Dyno correction factors can skew numbers in either direction."

That is why its called corrected numbers. Please post the SAE corrected numbers. Easier to compare when an engine is dynoed at 50 degrees vs 85 degrees

[Herr-Kuhn]

Just because you have an SAE correction factor done does not mean the same car on a different dyno will produce the same SAE results. The correction factors in any dyno can be altered to spit out higher numbers, this is done all the time. Plus dynojet measures time to accellerate a drum, calculates HP and then calculates torque. An eddy current loading dyno measures torque and then calculates HP. The algotithms are totally different, and word on the street is dynojets typically give higher numbers then these types of dynos. The dyno Mark has been using gives lower numbers than what I got this summer on a dyno dynamics unit.

Turbocharged cars are very sensitive to ambient temperature and there is no way a dyno correction factor knows if the car is NA or boosted, nor does it know if the room is exhaust filled, etc. I have yet to see a correction factor that takes all of the variables into account.

He just ran another pull today and the car posted 395HP/400+ ft-lbs on just 7.7 psig.

To play this "dyno-game" I will be certain to bring dynojet SAE corrected numbers to the table on the 32V car, otherwise my fan club will run around calling me a liar.

[Herr-Kuhn]

Here is a good article on why SAE correction factors can sometimes be misleading on a turbocharged car.

http://www.sdsefi.com/techdyno.htm

[Herr-Kuhn]

Of course there is one test that never lies. It is called:

"The rear view mirror test"

[sonett3]

The ttt is a hand full to drive now. I had a BMW m5 today egging me on , well i gave him a little taste of the ttt.