doc

I am currently biulding a 395 cu in stroker for my '87 IROCZ.
700R4 tranny.

Max flow of 395 cu in engine:

395/1728 = 0.228 ,,,,,, and 0.228x6,000RPM/2 = 685CFM

This equation says that an 395 will flow a max of 685CFM,, seems low to me, what do you think?
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'87 descreened MAF flows up to 720CFM depending on whos numbers you accept. So I should be OK with my descreened MAF.
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685CFM/1.3 = 527 flywheel HP This equation says that if I get everything that I can out of this engine, the max HP is 527HP. Pretty darn good!!!!
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I currently have a 52mm TB, this should flow nearly 900CFM, so this TB should be good for me, right?
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I currently have 24#/hr SVO injectors. At 80% duty cycle and 58psi fuel pressure, these injectors will flow 29.3#/hr and be good for 375HP at the flywheel. So I should maybe think about 30#/hr SVO injectors. What do you think?
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Also, do you think my SuperRam can feed this engine enough air and what cam if I keep the SuperRam? I was thinking a 218/218 cam.
If I go with the HSR, I think a 224/230 cam would be better.
What do you think????
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Its alot to digest, but this could lead to alot of good discussion.
The block is being machined next week, so I have some time to settle on the final solution.

JakeJr

A 52 mm flow about 750 and a 58 about 1000 cfm.

Just under 700 cfm is about right for the actual airflow. I've run numerous dyno simulatons and the airflow of my 415 is in the same area.

In order to get 500+ HP out of a 396 you're going to need a lot more camshaft than the two you listed.

From the dyno reports I've seen in the mags, you're going to need a minimum of 230 @ .050 and probably even more, depending on how well your heads flow, exhaust, intake setup, etc.

1.1 to 1.15 HP per cubic inch is a realistic power level with the engine still maintaining some semblance of street manners. Higher than that calls for a pretty radical cam and good compression.

Jake

doc

My HP goal for this project is 450 to 460HP at the flywheel which might translate to 400RWHP. The goal is actually 400RWHP on a chassis dyno.

Also, I do not expect to turn the assembly faster than 6,000RPM.
In fact, if I let the tranny do its own shifting, it will likely shift at about 5400RPM.

I want to tune on the car all of this year, I burn my own Eprom chips. After getting the best out of this combo this year, I might install a SC in Summer 2005.

TKOPerformance

One thing that is important to keep in mind is that flow numbers aren't as critical to EFI systems as they are to carb systems, unless there is a restriction. All my experience has led me to believe that bigger than stock MAFs (not much option here for our TPIs) and TBs make more power, with little to no loss of low end. My 5.0 Mustang went .15 seconds quicker in the 1/4 with a 65mm TB and a 77mm MAF. The car was stock at this point, except for cat back and no cats (the times I'm comparing are with only the exhaust, and then with the exhaust and the TB/MAF).

I'd go with a 58mm TB, and open up the MAF as much as possible.

24 lbs/hr injectors are good up to about 400HP at the crank. 30s with go to 450. You should probably consider 36s.

The SuperRam will be fine.

Your cam selection is too small. Your power goals are unrealistic with a cam this small. You'll want 275ish advertised duration. You shouldn't need a dual pattern cam with aftermarket heads. What heads are you going to run?

doc

TKOPerformance,

I will be limited to about 5400RPM I think with the 700R4 tranny and SuperRam.

So I was thinking that a 218/218 cam but higher lift like around .560" would be the ticket (might get me a few tickets!!!).

The LPE 219 cam for SRs has been recommended in another thread.

At first, I liked the 224/230 cam (Comp Cams XR276HR), but now I feel that it will make its max power above my RPM limit.

What do you think?

JakeJr

I'm running a 224/230 @ .050 (275/281 advertised) CompCams hydraulic roller. Had it custom ground from lobes listed in their catalog and ground on 114 LSA; .576/.544

Depending on the varaibles involved, torque peak ranges from 3600 to 4200 and HP peak from 4900 to 5400.

I use the $600 Engine Analyzer Pro computer simulation program which allows the entry of specific intake parameters - such as port lengths, diameters, taper, opening measurements, etc., etc. The smaller heads with 170cc ports peaked lower and the larger, like the Edelbrock Victor Jr 215 cc heads, peaked the highest.

My cam idles at 800 rpm pulls 14" of vacuum, closed loop, idle, in gear and 18" above 1200 RPM. No vacuum brake problem.

Hope this helps.

Jake

Roostmeyer

iTrader: (3)

I would search for ski_dwnit ?sp? he's running a very well ported 407 superram with SVO 24 lb injectors into the very low 11's. I still think the smaller injectors are killing him on top, but if its an issue you can get by, but if it were me the 30lbers would be worth it especially if you use the HSR. I would shoot for 230/240 on 114 LSA or something a little smaller for the HSR intake. Its ok because you'll need a custom ground small base circle cam anyway so you might as well take your time in a computer sim. and find the best cam you can run period.

For the Super Ram Intake I would use a ~222/222 on 114. Medium lenght runner intakes tend to like single pattern cams.

Anyone with a ~230/240 on 114 LSA cam in a 406 here? I've been wondering how well it idles and if power brakes are a problem? I don't think I'll be able to build my 400 for a long time but I can at least look at the block in my garage with illusions of grandeaur

Jake Jr. Where do you think your peak hp is at? I was thinking that cam somthing slightly larger with a bigger exhuast lobe for nitrous or supercharger.

JakeJr

Well, it all depends on what you are looking for and how you want to use the engine.

I built mine specifically for low and midrange torque. So I selected parts that I felt would give me that.

I used Engine Analyzer Pro and tried all sorts of different combinations - heads (using the flow numbers from both Chevy Hi-Performance Magazine and from the website of the company that makes the different heads), different LSA, duration specs, etc., on the camshaft (I only run CompCams camshafts but I plugged in a lot of their different profiles).

I researched and plugged in all the dimensions of the intake manifold, siamesed runners and plenum, then I measured all the openings that I ended up with after following MadMax's lead on removing the dividing walls, etc.

I juggled compression ratios, rocker arm ratios, on and on.

What I ended up with was a listing of parts that best met my goal of low and midrange torque. I knew I'd be trading off high RPM HP in order to gain the low and mid-range torque I wanted, but that was fine with me since my car is a daily driver, 24/7.

EAP shows a very flat torque curve:

3500=450
3600=462
3700=468
3800=471
3900=473
4000=470
4100=474
4200=474
4300=475
4400=472
4500=471
4600=470
4700=470
4800=466
4900=459
5000=451
5100=441

Horsepower Peak is at 5700, but, again, the HP is very flat. I can post the #s if you want to see them.

The actual TQ and HP numbers will probably be different if the engine is run on a dyno, but that's not important. What is important is the curve (or lack there-of); the comparison of parts and how they effect the power curve is what I was looking for. I didn't want parts that gave me a big hump or bulge which would have resulted in a narrow sweet spot.

According to how the car drives, I met my goals. It pulls more like a super-charged car than a nitrous car if you know what I mean.

Hope this helps.

Jake

JakeJr

Here are the low end torque numbers in case you're interested:

2000=386
2100=400
2200=413
2300=418
2400=430
2500=441
2600=443
2700=447
2800=448
2900=445
3000=445
3100=445
3200=445
3300=445
3400=448

Jake

doc

Jake,

That is really awesome!!!!! you're the man.

475ft-lbf of torque would feel really good. I am in your boat on the low and mid-range torque desire. I think that my goal should be a torque goal and not top end HP. I dont remember who said this but it goes: "biuld for torque, the horsepower will take care of itself".

My car has always been street/strip car, but mainly street. It has to be realiable and a daily driver also, sometimes I drive it to work. I take the car to the dragstrip maybe 3 times a year.

JakeJr

Here's something else to consider.

When I bought the heads I have on the engine now, I was running a 355 CID with a ZZ9 camshaft. The heads I bought, Edelbrock Performer RPMs, have 170 cc intake ports, great velocity and were priced right. For me, they were the best (all around) for the engine setup I was running then.

Now that I've changed engines and am running a 415 CID, I wanted to know if those heads are smaller than optimum for the size engine I have and the new camshaft I'm running.

So I did some back to back dyno simulations to see what difference changing just the heads, (leaving everything else the same) would make.

I took the head flow numbers of the Victor Jr heads - 215 cc intake ports 2.08/1.60 valves - from the same site that I got the flow numbers for my Performer RPMs, Chevy Hi-Performance.

I plugged in the different valve sizes (2.08 Vs 2.02) and port CCs -215 Vs 170 - both intake and exhaust ports are bigger on the Jrs.

EAP showed an increase of about 20 lb/ft of torque from about 2500 RPMs on up. Torque increased to 496 @4300/4400 and 4500 RPM and remained flat just as the Performers had.

That did not seem like a lot, especially when you consider the cost of the new heads - about $1,300. To spend $1,300 for 20 lb/ft of torque doesn't seem to give a lot of bang for the buck, right?

But here's what's interesting:

Both sets of heads produce more than 400 lb/ft of torque from 2100 to just over 5000 rpms. BUT when you look at the torque over 450 lb./ft the Jrs make more than 450 from 2600 to 5200 while the Performer RPMs don't begin to make 450 until 3450.

Also, the Jrs continue to make over 450 until 5200 while the Performers stop making 450 at 5000.

So with the Jrs, 450 lb/ft or torque begins 900 RPMs earlier and continues 200 RPM longer.

Now, THAT'S AREA UNDER THE CURVE THE ENGINE CAN REALLY USE.

The increase in PEAK torque isn't anything to shout about, the the width of the torque band IS.

My advice is NOT to just look at peak numbers - like so many do when selectiing a camshaft or a set of heads - but look at the entire power band that the engine will normally be operated in.

Don't just consider maximum flow that a particular set of heads offer or, for that matter, the maximum HP/Torque that a particular engine makes. Instead, consider the entire power band that the engine will USUALLY see (Not just WOT blasting down the quarter mile).

Long ago I came to realize that no matter how much power you manage to coax out of an engine, there will always be someone who will make more.

Just my thoughts.

Jake

doc

Jake,
Thank you for all the help. Do you have the 5200 to 6000RPM torque values?

Also, what valve springs are you running?

I think that I will be using 1.6 ratio rocker arms and a valve lift of about .560". What valve spring can I use???

Also, why 114*LSA? I was thinking 112*,, what effect does the LSA have on torque and HP? location of peak torque and peak HP. I am under the impression that higher LSA angles raise the peak HP RPM.

JakeJr

Here are the torque number you asked for:

5200=432
5300=425
5400=417
5500=411
5600=408
5700=402
5800=395
5900=386
6000=368
6100=357
6200=340
6300=325
6400=307
6500=292
6600=276
6700=263
6800=208
6900=174
7000=147

7000 is as high as I set the program to calculate. I knew it would be well above the power peak but I just want to see how much power would fall off.

114 LSA gives a wider (broader) torque range; reduces valve over-lap, increases idle vacuum and smooths out the idle.

In choosing the LSA for the camshaft I had custom ground by CompCams, I followed Myron's (TPIS) recommendation on how to build a torque engine. Keep the duration short and the LSA wide.

A narrower LSA will increase low and mid-range torque, but the torque range will be more peaky; over-lap will increase, vacuum will be lower, etc.

By switching to a larger set of heads - I used Edelbrock Victor Jrs for the sim - peak torque will improve to over 500 lb./ft. at the same RPM (with a little tweaking rocker arm ratios); in addition over 450 lb./ft of torque will be available as low as 2600 RPM whereas the Performer RPM heads don't hit the 450 mark until 3450. The Jr's maintain over 450 lbs./ft until 5200, which is 200 RPM higher than the RPMs.

So the big torque will come in almost 900 RPM earlier and last 200 RPM longer.

JakeJr

Forgot this:

I'm running the optional springs that came with the Edelbrock Performer RPM heads, they're 1.47 OD, 125# seat/340 # open. They're good for .575 lift.

Those springs were requested at no additional charge when I ordered the heads from Summit.

Jake

doc

Jake, thank for your help.

Also, I want to thank everybody above for their contribution and advice.

Jake, can you run something?

For the same sim above, can you change the cam specs to 222/228 with lift 0.540"/0.555" (1.52 rockers), 114LSA.

Again at 112LSA.

Is this asking too much of your time?????

My goal is to move the peak HP value down to about 5500RPM and not loose the area under the torque. Your idea of area under the torque curve is very good.