TQdrivenws6

I just got back from the dyno and the car seems like it is down on power. I got the tune dialed in so it is happy on fuel and timing (no KR) The graph is very smooth and looks like it should as far as shape. I will get a graph loaded up shortly. The datalog looks very good, there is 1" of vacuum at peak rpm at most so the intake system seems to be doing its job.

Predicted numbers were 450rwhp / 420rwtq SAE, it made 405rwhp / 385rwtq and I am looking for any ideas.

Thanks,
Chris

engineermike

Sorry I don't have LE2 head flow or cam spec's memorized. Also need more info on the exhaust system.

T/A KID

TQdrivenws6 what dyno was it on (mustang), what is the A/F ratio like across the Board and high high were you reving it to? Who did the tuning and how long did it take?
How old are your LE2 heads??
Good question, still running a Magnaflow exhaust, and whats the rest of the setup?
You do have a 9inch but I don't see that taking away much more than a Standard 12-bolt.
Are you running the ported Bret Bauer Super Vic your numbers should BE in the 450+range. With a LT1 intake we see LE2 setups in the 420-435RWHP range on average and thats a intake that flows 12-15% or the heads. A ported Super Vic would be WITHIN 3%. If your heads Flow 275 you should see about 265 CFM to the piston instead of the traditional 230 or so CFM with the LE2 heads and Lt1 style intake.
To give you a good idea on how well a Good intake is needed, Tony Mamo from AFR stated that with a 205 AFR mongoose head that Flows 300CFM at .600 mated to a Ported 90/90 Fast setup the engine only sees 265CFM to the piston. Thats why you usually see 346 H/I/C Ls1 cars in the 450RWHP range, which is where you SHOULD BE, its all in the topend.

My buddy is putting together a 355 LE2 setup with a Ported Vic JR and we are shooting for 450RWHP through a 12-bolt M6.

TQdrivenws6

First off, it was on a dynojet 248c. Here is the graph:
new setup

new setup

Head flow numbers are as follows:
Lift....Intake.Exhaust..E/I ratio
0.050.....36.4....27.6......75.8%
0.100.....65.8....54.6......83.0%
0.150...100.0....80.1......80.1%
0.200...136.6..103.4......75.7%
0.250...163.5..123.9......75.8%
0.300...193.0..140.4......72.7%
0.350...220.3..154.9......70.3%
0.400...240.8..171.4......71.2%
0.450...253.8..177.2......69.8%
0.500...263.9..181.7......68.9%
0.550...269.9..187.7......69.5%
0.600...272.7..189.6......69.5%
0.650...273.9..191.0......69.7%
0.700...271.0..192.0......70.8%

Average.197.3..141.1......73.1%


The cam is 23x/24x on a 10x .6xx/.6xx lift. The valvesprings are setup with 1.800 height to accomodate the lift. They do not bind.

The exhaust is a full custom setup. Jet Hot LT's to a dual 3" to single 3" y-pipe. Immediately after the Y there is a 3" DMH cutout. There is less than 1hp (within dyno error) difference with the cutout open vs closed. After the cutout it goes over the axle into a single 3" in dual 2.5" out Magnaflow muffler.

Here is the old dyno from the 383 LE2 setup with a LE ported intake and monoblade. The cam was 23x/24x .56x/.54x on a 109 or 110 (can't remember)
old setup

old setup
You can see the valve float from the comp 987's being over reved.

T/A KID

Who setup the cam and valvetrain on both setups, Bret?
Its kinda of weird that there was only a 1hp difference between the exhaust and the cutout. 3inch Y-pipe to dual 2.5 through a muffler would almost have to be more restrictive than just leaving the cutout open, but 1hp is weird.

What type of porting was done on the super vic and do you still have the 90mm TB, any problems with throttle tip in on normal driving?

Where the dyno runs done at the same place, and was anything else changed besides the cam and intake??
Any track times before the new setup, could be just a Faulty dyno runs, if so go run it again and check out the MPH between the runs.

Whats the CR on the motor?

I hope more people chime in on this one, cause you should be in the 450+ range, I have been around a Few converted single planes in my day, one being a Super Vic Bret did for me.

96speed

My LE1 heads flowed 252 and I made 420 (5200) with a solid roller/stock intake - all this with an out of wack valvetrain.

From the graph, the car looks like it is running ok. How does the car drive? What do the plugs look like? It is "making" power up to <7k rpm. The graph makes it look like the valvtrain was setup properly - no crazy lobes/bad springs.

Hate to say it but it has to be in the heads/valvetrain. Motor might be choked down with everything .

Ryan

Ryan

T/A KID

Another thing, the Super Vic has runners that are between 5.5-6inches, that is basically double of that of an Lt1 intake, and the TQ production seemed better with the Lt1 intake. It seemed that the cam was not a real drastic change a few more degress or on the intake and exhaust and around .40 or so more lift.
I don't think the heads are the problem even though I would like to see some Ported AFR or trickflows or possibly some SBC GEN 1 heads reveresed cooled . The only thing the Single plain intakes are doing is helping the loss of CFM from the Lt1 intake and possibly moving the powerbands uppward some (mainly the TQ curve), and I would think tuning would be easier (as long as the TB is not having problems) since there would be equal flow in each cylinder. More Flow more power.

LT4POWR

I'm no expert, but here's my initial thoughts. The new dyno curve and a/f look healthy, but definitely low #s. Your old #s would have probably matched your current #s if you'd had adequate valvesprings. Was your new cam degreed properly? Is your head flow enough to support your cubes and rpm range? I'd be interested to see you runner volume and hear what the head/cam experts think. Seems to me like most good (max effort) stroker motors are pulling at least 290 peak cfm with larger (LT4, AFR, TFS) runner volume sizes.

T/A KID

I think the LE2 heads are usually in the 200-205 Runner Volume Size.

Where the Hell is Bret at when you need him, (Probably Drinking Beer since its a Friday night)

RACEON

I wouldnt sweat it. I took a Car to a dyno and made 425 rwhp/428 ft/lbs tq and went to another shop and it was down 25 rwhp. Same environment, same elevation etc etc. No tune change.
Dynos dont always tell the real numbers, and it was SAE. So, if it runs good, A/F ratio is where you want it and you think the tune is spot on, take it to the track and see what she will do.

TQdrivenws6

Joe had designed the LE2 cam previously, it was just one of his boiler plate middle of the road LE2s, nothing very out worldly. Bret did the new cam/valvetrain.

I agree. This was even the case before the new intake/cam. I've never managed to gain anything from the cutout other than knock retard unless I have the KS bypassed.

Pretty basic porting, just blending in the radii on the inlet to the ports, and a little at the intake flanges. Throttle tip in seems to be alright now that the TPS is working correctly, it does have a little of a lean but the car doesn't hesitate or buck.

Different place, the other one shut down temporarily and I don't believe they have reopened. The only other changes were a Racetronix kit (old pump was fine, just did it as precautionary), a Canton oil pan, MSD DIS-4, and a bunch of suspension items.

SCR comes in at about 10.5:1. The next time I do the short block, that will be bumped up but it shouldn't be low enough to totally kill power.

I agree, I really want to get it running to its full potential. The car feels very strong, but that could be that I haven't ridden in the car with sticky tires for just under a year.

The car drives very strong with pretty good street manners. BLMs are certainly within spec as soon as its off idle.

I haven't had a chance to look at the plugs yet, but I plan to next week when I can get a chance.

The long runners were the primary reason for going this route. I had Bret spec a cam to match the setup since the other would likely not match well at all. The torque peak is definitely higher in the rpm range by atleast 300-500rpm, but its just a lower number. I want to do some SBC heads in the future, but as always money is the limiting factor there right now.

The big one that you list there is that I didn't degree the cam. I am starting to think it may be off a tooth. I need to get my hands on a degree wheel and check that out definitely....."You never have time to do it right the first time, but you always have time to do it over."

The heads are a 205cc runner and the measurements on the intake ports are 1.910" x 1.110" at the pushrod pinch.
I have already been into contact with Bret and I'm sure he will chime in at some point. I couldn't blame him for drinking a few beers....I need a few

I've heard this before, but the sad thing is that this dyno is known for reading a little high and the old place is known for reading a little lower. A friends car put down 362rwhp SAE at the place I was at today and 347rwhp SAE 2 weeks later at the original place I went.

I do want to hit the track, and as soon as it cools down and I have a chance to look at a few things I will definitely go.

The car trapped 114mph in 2500+DA last year floating the valves so if it does better than that this year I will be happy.

engineermike

A simple compression check will reveal this. If the numbers are way outta' whack (<150 psi or >230 psi), then the cam may be a tooth off.

Mike

SStrokerAce

Chris called me about this on Friday and I've been racking my brain as to what's changed.

I know the cam works, i've tested that design and lobes in other things.
I know the intake works, that thing has put LT1 headed cars over 600hp on the engine dyno.

The change in venue is something I didn't know about.

Obviously the cam and valvetrain are right on with the smoothness of that graph and peaks occuring at the exact points that were predicted with this setup. I don't think the cam is off from the design, it would look uglier if it was but then again we don't know for sure. The setup will peak like that at that RPM due to the valve size and lift along with the intake, but the valve control will make it hold on as long as possible, which is what's happening here.

I wanna say it's a leak.... this is good reading in times like this
http://racingarticles.com/article_racing-67.html

Ben, as for the flow a ported super vic on a 270cfm head is about 1% loss at the most with the intake bolted on, it's when you get over 290cfm that you will see a difference.

Bret