I dont know if this topic it belongs here I just guessed, lol. I just picked up a copy of this and Ive been playin with it here for a good 4 Hours or so and its pretty cool. Just How accurate is this program, Ive been told its pretty close to the real thing but I think im getting some pretty high numbers for example on the motor im gonna be building this winter


383 LT4 4.030, 3.75 stroke
AFR 210 Flow sheets #s
valves 2.02/1.60s
12.50/1 compression
600cfm Intake flow-(i think thats what the Lt1 intake flows)
Long Tubes- open exhaust
Comp Cams solid Roller
110 LSA - 248/255 @ 0.614/0.621 0.050 lift
All on pump Gas


Peak HP = 614 Fwhp @ 7000rpm
Peak TQ - 546 Fwtq @ 5000rpm

These sound a little high the projected Dyno chart looks good though with nice numbers under the curve.


-john

 

The cam function kinda sucks on it. It simply guesses the lobe profiles. You can have two cams with the same advertised durations and be totally different. By changing the lifter type, you change the programs thinking for cam lobe steepness and radicalness. With it set at hydrolic flat tappet it pretty much nailed my stock heads and cam (came up with 410flywheel, dyned 357 at ground) and had the right curves and peaks.

Problem is, i had no idea what lifter type to use, until i had already dynoed the combo. With hydrolic roller selected, it wasnt even close.

They have a new program out which is TONS better from what i have seen of the previews and trials of it. Still havent gotten my hands on a full copy.

 

ummm.. are you planning on driving this car on the streets with that cam? Its gonna be a PITA with the solid roller, but you will get more power out of it... Also the LT1 intake flows a bit better than 600 cfm... esp with that kind of a motor, you should be looking to flow at least 1000cfm.

To answer your questions, DD2k seems to be somewhat accurate.. If you put it together correctly.. Looks like you have the flow numbers covered and the cam...

The power does look a bit high, if you want to send me a copy of the file I will look it over for you.. You can e-mail it to me at mleaf@speakeasy.net

Also.. why are you looking to run such a high c/r? Its gonna be tough to drive the car on pump gas without knocking and pinging all over the place.. Im going to be building a 355 with 12:1 cr and Im still worried about it. Although you do have a big cam with a lot of overlap so your dynamic CR should be waay down from your static.

Good luck with it!

 

Im still playing with the settings but im reworked the cam selection to a get the TQ and power down in the RPMS cuz i really dont want to be spinning the motor that high, its really gonna only be a weekend warrior so the SR factor doesnt bother me that much. The new #s for the cam were

110 LSA SR
235/245 @ 0.600/0.600 @ 0.050 lift
Peak HP 596@ 6500
Peak TQ 556 @ 5000

There still a little high but there a step in the right direction that I want.

Ill try and send you the file.


thanks,
-john

 

Email sent


-john

 

Sounds good.. I will try to take a look at it in the morning and post a reply.. Im on my laptop right now and I dont have DD2k installed on it yet..

Happy Turkey Day!

 

I'd be surprised to see that 235 cam peak at 6500 in a 383. That cam is close to the GM847 and mine peaks at 5800 in a stock motor. I know the lobe separation will move it some, but 700 rpms in a bigger motor sounds a bit much. I think the main problem I've found with DD2K is that its very easy to duplicate numbers accurately in hindsight, but not before hand. FWIW, I just tend to move all the numbers down about 800 - 1000 rpm, and the power levels and curves have matched all the motors that I've made in it and dyno'd.

 

Brain has hit upon one of the problems I have found with it. I have all the updates to the program but they do not cover port cross section. This has drove me crazy tring to find the missing link.

This is the reason he make peak power so low with the 847 cam. My motor on the other hand with ported heads peaked at 6,900. Then again it never peaked with the stock heads all the way to the rev limiter.

The program does not let you input for the cross section and must use a fixed number. I found by using a big block to start with and input all my small block numbers I can get the results I am looking for with a set of heads that have the correct cross number and My flow numbers

It is no more then a tool. not the sharpest tool but a tool just the same.

 

I don't know how you all got so lucky with accurate results.

My entries were accurate right down to selecting the flow files
for my heads, valve timing from the cam card, etc.

The program was off b more than 100 HP, wrong peak RPM, the curves
looked nothing like my Dynojet run (even when you consider loss through
the driveline).

For the size and cost of the program, I can't see how reliable it would be.

 

Get the Engine Anilizer Pro from Performance Trend it is much more accurate.
235* cam is NO problem on the street,262/268*@50 108 mechanical rollers are driven on the street down here with no problem.

 

If thats the case ill probably look to move back up to the bigger cam, I used the AFR 210s flow chart but I will be going with a Set of TFS LT4 heads and a complete custom P&P job, I figured the results should be pretty close to the AFRs if not better. I guess if im gonna spend the extra to do a solid roller I might as go a little more radical than an off the the shelf HR such as the 847. I think that with a good tune it should be pretty tolerable on the street even with a cam like the 248/255 as long as I dont make any significant trips with and if I do It will be to the Track and then ill prolly trailer it. I just want to have a car that I can drive not everyday but a fair amount but be considered a little much for doing so.
If I step the compression up that high 12.50:1 I will more than likely have to run a either race gas a mixture right?

But lets say I go with a lower compression say 11.5:1 or less and and am able to run pump gas and increase the streetability of the car?

thanks for all of the impute,
-john

 

I am running 13/1 on pump gas.Like I have been trying to tell you,the static comp don't mean s***. You need to figure your dcr at 8.9-9.0 and you will be OK on pump gas and the 248/255 is still small.You can take trips in it just like always,just don't load up and go to LA. A 250I/260E@50 is plenty good.

 

A250/260 on a 108 + 4*advance will make in the neighborhood of 650FWHP@6500 and 580FWT@5000,on pump gas with 12.5 to 1 comp and still be plenty drivable. Like I said don't load up and go to LA. Your gear will let you know about trips not the cam. You can run a 4.10 and be in the middle 3's in overdrive.

 

Ooops I guess I missed that in your other post about the dcr its been along day. lol. I dont plan on going to LA anytime soon he he but I agree about he gear. The car will be a M6 when its done and you were refering to mid 3s in an auto with 410s correct.
-john

 

9.0:1 DCR Is still pretty tough on a motor unless it's perfectly done.

In those Evans NPG threads Mr Horsepower wrote about a 10.6:1 DCR 93 Octane pump gas motor! Wow!

You could run some high Dynamic and Static compression on a pump gas motor but most likely it's going to take away from the drivability because you will have so much cam in there.

Remember that HP peak is not only dependant on cam duration, cross sectional area, runner length, header dimensions and cubes all have a big effect on it.

John, the only thing to look out for on a SR motor is the lifters and springs and how they are going to work together. Racerdude is lucky to try out the Schubeck lifters on his motor but most guys look at a $1000 set of lifters and tell you that you are nuts! Once you bust a roller bearing on a lifter you will be one pissed of ****.

Bret