Promised the 3.8 dyno graph, here it is...
 

Hinted a few times in recent threads we posted about the 3.8 we were building. Here is the dyno plot. Very pleased. Notes about the build are in the chart...

http://forums.pelicanparts.com/uploa...1575003730.jpg

Cheers

Impressive numbers, Jeff! Were there pics of the engine I missed? What's this going in?

Wow Jeff! Love the flat torque curve!
Question about the ported Heads: Were only intakes ported or did you also remove exhaust ceramic liners?

^^^ Ported was perhaps not the correct word. Blending of the guide boss and general clean up would have been more accurate. Liners are still in place.

Engine is in a 964.

In the pics you can see our 100% CF RS Style heater fan bypass tube made specifically to clear the ITBs. This tube is part of our Turn3 Autosport 100% Carbon line of products.


http://forums.pelicanparts.com/uploa...1575093344.jpg
http://forums.pelicanparts.com/uploa...1575093420.jpg
http://forums.pelicanparts.com/uploa...1575094005.jpg

Cheers

What compression ratio?

Impressive numbers, especially for a streetable motor! It looks like hp is still climbing at 6500 when the graph stops?

I have always thought the more important number is the HP per $ and HP per LB, I think that is a great way to measure engines value/performance.

Either way this is a sick engine, that i'm sure it twice the cost of my entire 911 lol

^^^ This motor is not inexpensive. At some point the HP/$$ value starts to change. You can get a few HP for a few $$. A few more HP for a few more $$.

To get the sort of HP/Tq this motor makes it does cost. But, this motor (like all of our custom builds) is built with all of the best components. It costs between 40-65% of what some in the industry will charge, even though they largely use the same components. I would put the driveability of this motor (and all of the custom HP motors we build) up against any similar build and not be worried at all... Our low dollar helps keep the retail cost of the build down as well.

Cheers

I want one.

What lobe centers on the cam did you select and what compression ratio did you end up with on the 3.8

11.5:1 DR. Lobe centers are 113*.

Thanks Jeff
Curious, are you running pump gas and if so, what obtained?
JA

Octane?

91 Pump up here. However, here in BC we have a special blend of "low carbon" fuel which does effect power ratings. Many around here have proven using 92 from WA state will create a very noticeable bump in power on the dyno.

Cheers

Gawd, I didn’t realize you guys had worse fuel up there than us. Amazes me that a lawn mower would run let alone a H.P. Porsche motor.
Super nice build btw. You must be happy with that torque curve. Or lack there of. Pretty darn flat.

What size are the ITBs?

What cams are you running? I am impressed by the flat upper torque curve. I’ve seen similar with VRAM but never thought you’d get there with ITB’s.

Cams are a DC24. We chose these after consulting with John (which we have been for years) to get a big wide torque curve/plateau. With all of these motors we want the throttle response and power the ITBs can make. But we want to chose a cam that doesn't make the motor a more typical ITB motor in terms of its power delivery. Cam choice, CR, displacement, exhaust all play into it. Then having an amazing tuning partner that can make the motor produce as much power as it can in all load/dynamic situations is key for us. Could we build a peaky version with higher HP? Sure, but that would not fit the requirements of this client.

Cheers

51mm tapered

Just curious, what cooling set up gets rid of all the BTU's that +400 HP creates for the engine and tranny.

Not a race car. Used on the street, won't see any significant raise in temp in the gearbox. For the motor, the 964 oil/air cooling is plenty sufficient for street use, as well as significant track use (with reasonable ambient track temps).

Full on race car? Depending on the race length (20 min sprints or endurance) we would want to log the temps to see what, if any, cooling was required. Thankfully with the ECU we can do that if it was required.

Cheers

What's your experience with the local Chevron 94 w/o ethanol?

Jeff
I must say that the use of stock rod bolts shown in this picture is a little alarming for a Hi performance engine, even if a streeter. I have never used a stk rod bolt in my life, is $100-125 worth the risk of a failure here? I was tipped-off to look by the backing out at 6500 with HP still climbing on your dyno ...who would do that?

Also , recognize , whomever is tuning -dynoing your engine is feeding you frankly absurd numbers as 410 hP, this is not going to happen in a million years w your combination of parts, well maybe w forced induction. I'd bet if you put it on a Dynojet it would make about 300-310 at the wheels SAE or 335-345 flywheel HP Max... There are no shortcuts to big power in these engines NA(sans boost).

Recognize a 3.8 RSR at high compression(way higher than where you are at for pump gas, way more cam, way more head flow, way more RPM, makes 380 max flywheel HP, w multi throttle body and plenum intake. Yes more can be made and many are achieving that at great expense, but are doing so by adding more of the formerly mentioned above, selected wisely to perform better together, but what you list here is well, simply not that .

When I read this nonsense I have to say I appreciate the comment of Steve Stillen and why he loves racing engines and racing vs being a tuner ;( paraphrasing here) when the flag drops and all are there to compare at full pop, the nonsense stops and we see who achieved what . There are many ways to hide w dyno numbers on streetcars.

We race.

Kevin
GAS Motorsport

Kevin,

You should go look at some of the other threads Jeff has posted dyno charts in. They all have similar hard to believe numbers. I would wager the uncorrected numbers are closer to reality.

"When the flag drops, the bull$hit stops."

- Jack Brabham

I have to agree with Kevin's statement. Today people running pump gas motors with stock heads thinking there making more power than a factory RSR 3.8 motor, that is a little alarming..... Not to mention their using 1 1/2" exhaust to make big power...

I never take chassis dyno numbers at face value. IMHO the chassis dyno tool is used to measure before and after changes and shape of HP/Torque curve. The engine Jeff built here has a great power curve. I wouldn’t get hung up on the numbers.

I learned early on in my motorcycle racing days that "chassis" dyno numbers were not to be used for comparative data when the dyno numbers came from different dynos. There was this one engine builder who always seemed to get more out of his engines than anyone else. His charts always had the biggest HP numbers. Yet, on the track, his engines did not pull harder than other builder's engines. In fact, his engines often did not pull as hard. He used a rather "optimistic" dyno.

The problem was that this engine builder used his dyno numbers as a way to get people to use his engine building services by suggesting his engines made more power than other builders engines....even when using the same components in the rebuild. He didn't tell people that the dyno he used was "optimistic" compared to most others. This builder built fine engines. Just not as powerful as he led people to believe.

So yes, it is proper to get hung up on the numbers when they don't make any sense. Especially when Jeff presents them as if they are realistic numbers.

We have found that a Dynojet w SAE correction is pretty repeatable, as we use it in The POC out West here many times a year at Race events. For the most , we get many cars to repeat within 2% track to track. This is why we settled on a 2% error for competitors. There is no reason to BS in our circles as you get put on the machine often if you are competitive. Alternatively, if you have big power and are not competitve, you are just a poor driver or bad car configurer and need to work on other dept's.

What The Original Poster represents is power levels about 20-25% too high w not really well configured or developed bits frankly. This, as an affordable alternative to expensive "comparably powered engines". I note again I see stock rod bolts here, which fail in stock application(low pwr and below 6700 rev limit) , so why build your 3.8 or any hot rod around them?

Like a buddy once told me and I adopted many year sago, "those who do it cheap, do it often".

Kevin
GAS Motorsport

Kevin,

I am sure Dynojet dynos are much more consistent today, dyno to dyno, than they were 20 or so years ago when I was racing bikes. Or maybe the car dynos were always more consistent relative to each other. Even with that, it is possible to enter your own correction factors and get whatever numbers you want. Then there are different dyno manufacturers to deal with and the numbers they report.

Fun stuff!

I don't think Jeff Alton is trying to deceive anyone, I feel he is just posting numbers his dyno guy is feeding him. The numbers are not attainable at those rpm's and the torque is too high. the numbers look off by about 25%.. I had a 4 liter on dyno not long ago and the dyno guy told me it was making 400 hp at the wheels..... I told him he's got something wrong as most 4 liters make about 350-360 hp at the rear wheels that I have done. I was excited to hear the 400 hp number then reality set in... WK

When looking at dyno charts, the first thing to notice is the peak torque and the cubic inch displacement. 1.4 lb ft of torque per cubic inch is about the limit for a street driven engine, across nearly all sizes and shapes of 4 stroke otto cycle normally aspirated engines. If it's a max effort race engine, about 1.6 lb ft of torque per cubic inch is gonna be the limit. If the power output exceeds those parameters, I'd question why.

I trust engine dynos more than chassis dynos. And I always look at the uncorrected torque.

FWIW, IMHO

Just checked dannobee numbers on 1.4 and 1.6. it is quite accurate in my opinion.

Engine output numbers
 

I always used an engine dyno because I had one.My best comparison was a real road test.My first shop was in Califon NJ.There was a slight uphill section after The River Styx Tavern for 1/2 mile on rt.513.Come through at 40 mph.and stand on it to the last telephone pole at the top of the hill.Learned a lot that way.Real world EGT & AFR with a slight uphill load.Most highest output is not the quickest from point A to B.This was in mid 1970,s.Nothing like the smell of 100 Octane on a Sunday morning.Ciao Fred

25 years ago I used a Bosch 02 sensor to tune carbs, 1 wire and a $20 sensor and a good DC VOM meter, 850 MV under a load full throttle seemed to be perfect. That is how I learned what carburetors liked. I also used timer from 4k to 8K to perfect the tune but 825 mv to 850 mv really did the best. WK

3.8 fiction
 

So you know folks , any proper Dyno has a weather station built in to its console, and one can trick it, or manually insert numbers for the current condition, but if you look up the conditions for various runs, the correction factors should be reasonable and can always be checked against local data. If the runs say SAE on them they have used the methods associated w this . These details may not always appear in folks postings so one should be alerted if you don't see SAE or STD correction. The difference between these 2 on a Dyno jet os about 1 %, not 25%. If you question this get the corr factor to remedy associated w the runs. But when folks try and estimate HP from one type of generous wheel Dyno to crank numbers, and they far exceed those a well built Race engine vs a very basic streeter engine , well there is a lot a-foul.

These numbers quoted on Tqe per Cubic inch and associated digression are totally meaningless in this discussion as this 3.8 Dyno graph from Alton's 3.8, which is far far less than a proper race engine, though numbers stated beat what Porsche could do on well done endurance engines. This was the contention...Upward and onward.

Regards
K Roush
GAS Motorsport

I agree again......WK

Not particularly aimed at anyone in this post but the Porsche world in general is full of hyperbole.
Quote From Ed Pink Unfortunately we have not progressed much in the last 20 years with the 2 valve engines
because it is difficult to communicate and share results, both positive and negative when so many bragging rites appear to be at stake.

Just get one of these setups. There ok! :D

AVL

Thanks
Mike G.