It was a disappointing day all around yesterday.

Anybody want to take a shot at what's wrong here?

The first graph is Allen's previous combo in my car (6spd.) but with AFR 195's instead of Dart 200's. He was making power all the way to 6300.

The second one is my runner combo on his previous engine. They are similar but his are bigger inside.

 

Are the graphs reversed ?

Out of curiosity, I just looked at the head specs for the 195AFRs and the 200s. (I'm not sure if I got the correct heads to compare.)
AFRs have bigger intake valves 2.08 vs 2.02 and have better flow numbers esp on the exhaust side.
looks like the head stalled out, the cam isn't quite right or valve springs gave up.
Been about 4years since I delt with the dyno daily.. Go easy on me.. lol

 

First graph is odd... torque curve remains fairly strong and flat til 5.2K rpm and then drops like a rock..... is that the intake harmonics having severe effects on cylinder filling? valve floating?

What was the cam specs?? may need more exhaust duration to keep power hanging on, but not going to help all that much if the intake harmonics are killing power beyond 5200 rpm. Definately strange. The other intake setup doesnt seem to have that problem, perhaps a better designed runner/base combination?

Second graph has much stronger midrange torque response...probably runner length and csa change that had good effect on boosting that rpm range. Runners also supported power to 5700-ish rpm..much higher than other intake setup. Looks like a stronger setup, more normal too. I wonder if its flow velocity /distribution throughout the intake that really changed flow dynamics into the cylinders.

 

The first dyno kinda looks like one of the rare C6-R dyno sheets I've seen. Just tried googling a sheet but can't find a single one. some sites are blocked cause I'm at work so I can't check all of the search results.

From what I remember the C6-R peaked lower, but had some crazy flat torque curve from like 2500-5500. Looked almost exactly like the first sheet posted.

 

Some tricks with the cam and restricted intakes can make powerbands like that but if that intake pulled to 6300 in a different car with different heads, it sounds like the entire combination was restricted due to velocity reasons in the port.... That would be the only big difference I can see between AFR and Dart heads in similar CC size. Even tho the AFR's have a larger valve and flow abit more onthe bench, the velocity is higher and can choke out earlier in the rpm range. The darts may have been able to support more rpm and thus more power or at very least, similar power. With that torque curve being so flat, i'd expect hp to carry way up into the rpm range but it clearly didnt.

But AFR's have been used to 6500+ rpm on other builds without choking too much. My 383 used the 195's to 6250 peak, flatline to 6500 and slowly dropped by 6800. Not much of a drop tho.

 

I wonder what the exhaust PSI is before/after the converter(s)? And if any vac is present in the intake while making a high RPM pull ?
For the numbers to fall like that i'm just wondering if there is any restriction anywhere in the system??

 

I was wondering the same thing (I wonder what the exhaust PSI is before/after the converter(s)? ) I think next time I will diconnect the pipe after the converters.
Our exhaust sysems are similar except for the muffler, his is 3 1/2" , mine is
3" but from the muffler forward they are the same. (with his previous combo, he has collector boxes now)

The kpa is right at 100 @ WOT. (3 1/2' intake duct).

 

Ron, I consider this as my hobby and yes a lot of work does go into it. Onward with the next long tube runner project.

At this point in time after all these tests some of us here locally think Don needs to give his exhaust system a hard look. One area would be the catalytic converters as they may have clogged up somewhat over time. An exhaust pressure test would tell the tale.

 

I wonder what 1 7/8s- 2" primarys with 2 3/4- 3" Ypipe with 3"cats and 4" cat back would do, if anything...

 

From what I've seen said by some experienced builders, 1 3/4 should handle 600-650 hp on the right setup. The big gains are in collector design and length, hence the exhaust tuning theory with termination boxes or open header extensions of right tuned length. Also primary pipe LENGTH is important. Too long will hurt power. 28-30" tubes work great for most builds for long tube headers.

 

On every build it sure seems like the more power you want to make, the Intake runners get shorter and the headers get longer... to a point of course.

I'm also wondering what siamesing the runners a bit would do? Pricey to make about 6 sets with 1" diff in lengths just for testing buuuut it would be nice to see those numbers also..

 

The math seems to be holding up quite well with this setup. With the next version I should be real close to where I should be regarding runner length. One other thing is I will be able to maintain the right cross sectional area all the way to the head this time around. With the current base the area around the injectors is smaller than it should be. All these factors affect the strength of the harmonic wave pulse.

 

Maybe a dumb question but are you using the same dyno?

 

"Maybe a dumb question but are you using the same dyno?"

Yes, the same dyno.

One thing we did change while driving around and doing the initial tune was lower the spark advance from 30 degrees to 28 degrees in the 4400 to 5200 rpm range thinking that would cut back on the knock count.

Now that I look back on it I am not sure that was the right thing to do. On the chasis dyno I was running pretty lean and I believe that was what was causing the knock count. So the next time on the dyno I will have the 30 degrees restored and see what happens. The 30 degrees is what worked best on the engine dyno. We were dealing with other issues on the chasis dyno with the car not running right such as bucking, SES light coming on and so on.

 

I'm certainly disappointed by the top end performance of the engine. The "bucking" you mention could be fuel related. Are you sure your fuel system is sufficient for the need of the new combination? I assume you're monitoring exhaust temps for lean condition. The Torque curve looks like too small a cam. More specifically duration and maybe LSA too. Your heads flow to .1000". I could see you using a cam with .700 gross lift. Since your new combo should make power up to at least 6,600 rpm, and will have to to make 600 crankshaft hp from 368 cid, I could see it wanting 250-260 degrees at .050. I understand your cam is cut at 114 LSA. This should be about right.

I understand your need to remain emmisions compliant. Unfortunately, without supercharging, I don't know if you'll acheive 520 rear wheel hp from 368cid without pushing the envelope a little more. I am not at all convinced by your unstellar dyno showing that your new combo cannot produce another 100 hp. You may just need to do some experimentation with cam lobes and fuel injectors.

Good luck and happy holidays!

 

"The "bucking" you mention could be fuel related."

Actually I think I needed the eprom reseated in the socket of the memcal. We went to download the latest data from the dyno and it would not take. So after re-seating it everything now works. That was probably the problem. We might do one more dyno run.

The goal is around 450rwhp but I am not sure if I will make that. I might get 550hp at the flywheel which should work out to 440rwhp. ASE doc you are right in that a bigger camshaft would make my life a lot easier. However the car really does drive good on the street and I am very happy with it. By the way I just picked up the welded intake manifold today for version 2. I will go ahead and post a picture of it in a little while for those who might be thinking of doing something like this.

 

I was thinking about the bucking prob today but it sounds like you fixed it. I had a similar prob with my 89 formula and mine turned out to be a bad power wire by the coil.

What intake are you having welded? Edlebrock or ?? Whats that run to have done? PM if you don't want it known. I'm thinking of doing one like yours. Its going on a car that must look 100% stock, If you know what I mean..

 

For all the work that you've put into this Custom Intake , you'd be crazy not to dyno it again!!!!
You've obviously done your homework... Don't let one crappy dyno session ruin it...
That intake has the potential to blow everything out of the water!!!

 

I am doing an Edelbrock this time around. It has a lot more meat in certain areas and does not require as much welding. For a milder build the original Accel is the better intake. So far I have $250 into the welding as shown in the attached picture. I will probably double that amount.

From the previous dyno run I could tell that the power was dropping off shortly after 6500rpm which is what I thought it might do. That is the reason for version 2 with the corrections. One thing this test did prove was that you can make good power with long tube runners and at high rpm. Here is the picture of the next intake after the welding. Next up is the machine shop.

Edit: by the way where the red dykem is in the picture there is machining but it probably is not obvious.

 

If your goal is 450 at the wheels, you don't have far to go. I am of course excited to see your next creation.

 

I hope that my input isn't seen as criticism. I know that there are some great minds involved in this project. One thing I caught from an earlier post is your mention of ignition timing. You said that you had set the timing at 30 degrees between 2,500 and 4,000 rpm. Remember that whatever advance produces max torque at a given rpm, the advance will have to increase from that point with engine speed in order to continue producing max torque.

If we think back to engine performance 101, we remember that while the speed of everything in the motor increases, the time it takes to propogate the flame front from an ignition event stays the same. Therefore, in order to maintain ideal cylinder pressure, ignition advance must increase with engine speed. This is of course in addition to the initial advance curve from idle to the beginning of the torque curve.

I'm sure this is nothing new for you. Just something that struck me.

 

The reason for pulling 2 degrees of timing out in the 4400 to 5200 rpm range was that I thought that would be where peak torque would fall. Peak torque is the highest VE point and the most likely area for detonation. We did this before I got on the dyno and after seeing the dyno results I missed the mark. I will restore the 2 degrees of timing and see what happens at the next dyno session.

As to Version 2 I will be going out to the machine shop this Tuesday and probably Wednesday. The project is moving right along at a faster clip than the last one. I think we can get one set of runners ready to weld up next week.

 

I have to agree here.......too much work in this project not to try it again with the changes you had mentioned..

 

Making some good progress on Version 2 of the Long Tube Runner intake. With the shorter runner I hope to move the power band up around 400rpm. It was much to low in the previous version. Here is a progress picture.

 

Guna be pushing Super Ram looks.. Looking good

 

A wild guess on max torque with this intake?...

Btw,... Happy 2012 Everybody!

 

"Guna be pushing Super Ram looks.. Looking good"

Funny you should mention that. Here is a SuperRam project we are thinking of doing next. It will have the D shaped runner as shown on the right port in the attached picture. With the Super Ram we will be chasing the 3rd harmonic wave. The D shaped port will give the proper cross sectional area.

The current intake has produced 420rwtq with a 369 cubic inch motor. Maybe 525 torque at the motor? I don't think there will be much if any difference with Version 2 except hopefully peak torque will occur about 400rpm higher in the rpm range.

 

What about cuting the cast runners away and using your 2" runners but in that length?? It seems like the D port may take some serious welding!

 

Whats the new goal for runner length this time, is 20.33 (total) sound about right? and did you also lower the plenum floor on this one to get the desired cross section. Sorry one more question would SLP's T-ram lower base manifold be legal in Cali, it does have an egr and I would think that they were 50 states legal at the time.

 

I have already looked into using the 2" tubing for doing that on the Super Ram and I have one already cut to length. That would be easy enough to do. From what everyone tells me the D shaped port is better in a turn than a round port. With the D port I can have a CSA of 3" down to the base and then taper that down to where it meets the head. The welding won't be to bad. Just more grinding though.

As to the new length I should be at 20.625" based on my dyno run with version 1 of the long tube runners. I don't believe the T-Ram was "legal" in California but was in the other 49 states. I have never seen a T-Ram in person but it would be interesting to inspect one.

The floor of the plenum will be completely removed as will be the back wall, the right side and most of the left side starting a couple on inches back of the throttle bracket will be removed. The plenum will sit 5/16" taller than stock. The new floor will sit just above the EGR valve and taper up in the back so that I have enough room to adjust the fuel pressure regulator.

You might be able to tell in the picture by looking at where the factory runners are bolted to the plenum that the plenum is also a 1/2" forward of the factory location. So I will be able to improve on the plenum size again over the previous version. The sides will have more volume and the bottom volume will be maximized.

 

I think yu may be able to get away with a t ram. I live in CA and I don't have a cat conv, just a 3" pipe. But check this out, when I registered my 86 IROC, I didn't have to do a smog test nor was my Camaro inspected. But if you do buy from a store, they will refuse to sell to a CA adress if the product is not up to CARB standards (California Air Resources Board).

 

I read the post where you explained what was a 369.. but I can't recall the bore/stroke

And 525 at the flywheel sounds right.. your current dyno number is the one that intrigues me, I would of tough that with your E-water pump and the lightweight crank and its coating there would be a bit more power to the wheels

 

Are you joking, its a N/A TPI with all emissions equipment on and he passes California C.A.R.B., I think he even has his A/C working, I'd say 423whp is outstanding.

I think he has a 3.625 stroke but at 30 over it rounds off to 369.912 which most people would call it a 370.

 

"I read the post where you explained what was a 369.. but I can't recall the bore/stroke"

I know, it is a long thread. Bore is 4.060" and stroke is 3.562". I am certainly looking for more power to the wheels. The question becomes, if not? Why not? Where is the missing power? I should be able to get around 550HP at the motor. We shall see what the latest intake version does.


Chevy86 IROC-Z, do you have to smog in Holtville? I don't think you have to smog in places such as Blythe or Inyo County. So in those place certainly there would be no problem running a T-Ram. Also some techs may not know the difference with intakes and pass it anyways. These cars are now 20+ years old.

 

The worst part of a T-ram is the runner intrusion in the plenum right behind the T-body and the weight of it all.
The T-ram has a EGR provision but I don't think the Hawk could b sold in cali. I think it was more the cam than intake.
The hawk used aluminum vet heads and really didn't have the egr hooked up to the heads.. The vet used a external tube to feed the intake EGR and the fbody used the center port in the heads.
I have 2 here if you need a pic or 2..

 

You are right about the Hawk not being able to be sold in California. I have seen pictures of the T-Ram and have studied them in detail wondering what I would do to improve it. I have just never actually seen one.

 

I was thinking of ditching the uper half and just make a completely new top half, but if it wont pass then whats the use.

 

gp90gta.. no I'm not joking.. I wrote "a bit more power",.. not quite the exaggeration that you assumed to have my opinion reduced to joking.. neither remind me what the build is.. what makes you think I'm not aware of the situation?..

1989GTA Oh I see.. interesting..
I think the shorter runners are gonna get along pretty well with the short stroke

 

....and another progress picture of version 2. The drivers side runners are now complete. This coming week the back of the plenum will be blown out and exended.

 

I like where this version 2 is going. Might I suggest building a completely new plenum that is taller as well as wider in order to un-shroud the runner entries. Your new design is closer to my own idea but mine would have two separate plenums made from large diameter tube.

 

He will need a cowl hood to reall do that tho

 

I was a little worried myself about the shrouding that might take place and I did what I could to minimize it. It is not that bad and looks in person better than what the pictures might portray. As to the taller and wider it is about as tall as I can get it and still have it fit under my strut tower brace which I desperately need to help keep the body from flexing to much.


The other design criteria is to keep it "somewhat" stock looking by retaining the top of the factory plenum and the side where the throttle bracket bolts onto. Enough years have gone by and the smog technicians are not on top of the details of what a factory TPI looks like. When I am done blending in all the welds and some sand blasting I hope to make it look like it was cast that way.

My fingers are crossed that Version 2 will do what I want it to. We shall see. I was toying with the idea of doing a modified SuperRam if for some reason this does not do as expected. I would build the runners as shown in the above post to get the proper CSA and runner configuration in the curve portion. If I did I would drop down to the 3rd harmonic wave as used in the LSX intake manifolds. I may just stick with this one and finely detail the car.

Edit: I wanted to add that I will be dropping the floor of the plenum a little more than I did on version 1. Trying to get a little more plenum volume. This will help slow down the airspeed in the plenum somewhat and help with better air distribution for the cylinders.

 

Here are a couple of more pictures with the back of the plenum extended and completed. Next up we will blow out the rest of the bottom and drop the floor down as much as possible to increase the plenum volume.

 

Here is a front view. The throttle body entrance is yet to be opened up to match my monoblade throttle body.

 

I'm guessing that your gonna shave off those egr port walls right? How much have you invested up to this point?
I envy you right now. Lol

 

"I'm guessing that your gonna shave off those egr port walls right?"

Yes, that is correct. The plenum floor you see through the two ports will also be gone and lowered. My out of pocket costs so far are probably under $600 as I am not keeping track. This one will be cheaper than version 1 as I have found ways to do things differently and cheaper.

 

I salute you. What really makes me question aftermarket parts such as Edelbrock hi flow, accel runners, SLP runners, AS&M as well as the intake bases, is that the expenses that you have spent is around the same costs as the runner and base, but with a huge difference, volume of airflow. Your method out flows the aftermarkets. You should be very proud of yourself. Keep up the good work man.

 

Do you mind me stopping by your area like in about a month or so? I'm gonna go to Universal Studios in Hollywood with my wife and kids. Would love to see in person your setup.

 

I should say that does not include the cost of the base and the plenum. The cost is for materials(tubing, aluminum plate) and welding etc. I suspect the total when it is all said and done will be under $1500 dollars. I consider this to be my hobby.

 

You need to stop by Don's shop AKA the SoCal Third Gen clublhouse. We could meet up there. There is usually something going on. Here is Don info.


Don Lorentzen
2831 White Star Ave #A
Anaheim, CA 92806
(714) 630-1502