Finally have all the bugs worked out of my new LT1. As most of you already know, I was having valve train control issues since March that were driving me nuts. After lots of discussion with LE, we decided to pull the LE1.5 cam and replace it with the LE1 billet cam which would not be as hard on the valve train. The difference in cams was a slight reduction in lift and less aggressive lobes. The LE1.5 cam would have been a great strip cam, but I wanted something that would be more reliable for the street.

During the cam swap I also decided to replace my mid-tube headers with some LPP stepped LT headers as well. I also installed dual Pypes mini-cats to keep the funky smell under control for when the ragtop is down. Here are my new engine specs:

355 CI. LT1 built by Kennedyperformance.com
11.1 CR
Mahle forged pistons w/ 6" rods
Stock crankshaft
LE2 GM heads ported by Lloyd Elliot
LE1 billet camshaft
LT4 extreme duty timing set
Patriot extreme dual coil springs
1.6 Comp pro-mags
GM intake ported by Lloyd Elliot
30# SVO injectors
52mm throttle body
ASP UD pulley
AS&M cold air induction
LPP long tube stepped headers w/ dual Pypes mini cats
Borla cat-back
E-cutout (open)
Midwest Fabricated 9" rear w/ 3.89 gears
Detroit Trutrack
Strange Chromeoly drive shaft
Spec 3+ clutch
Tuned by Bluecat

Just got back from the dyno and made:
412 RWHP corrected
363 RWTQ corrected


There are absolutely no valve control issues in my current setup. All of the valve float and bounce has been completely eliminated plus I picked up 20 RWHP to boot. Engine is very powerful with no ill side effects. Might have to tweak the A/F which appears to have leaned out a bit maybe due to the catalytic converters.

Special thanks to Lloyd for helping me work the bugs out and putting together a powerful combination. His assistance and support have been absolutely second to none. He took care of me till the project was finished and running the way we both knew it would. Thanks also to the board for all the help and support. Going to head to the strip in the next month or so. Looking for high 11's or near 12 flat's.



For comparison purposes, I made 301 RWHP/326 RWTQ with stock short block, stock heads, all bolt-ons except EWP on the same dyno.

 

Nice numbers, but looks to be a little lean.

 

1 convertible to another looks like you did a really good job putting this thing together. I am trying to do almost the same to mine. I have a set of kbdd sfc's that I have yet to install and that will be my final suspension piece (until I change my mind). I believe that you have the same ones. Anyway great job on your car and I hope that you enjoy it a lot.

 

The O2 sensor was stuck in the tail pipe and not screwed into the bung in front of the cat. Its possible that this is not the ideal way to monitor the A/F when using cats. When the dyno tune was done months ago, the A/F was flat as a pancake at 13 to 1. I am still going to get a tune up maybe this fall.

 

Nice job! Enjoy it.

 

I am glad you finally got some good results from your set up.

Pretty good for a mid 220 duration cam and 9" rear end.

Lloyd

 

Nice numbers Can't wait to see how she runs at the track.

11s should not be a problem in good air.
With some suspension upgrades and good tires, you should be there without any trouble.

You're making more power than I was when I pulled my 11.89 and with that
355, you're going to be able make use of more top end then I was.

 

real nice for such a small camshaft.

As long as your happy with it great......Glad you got everything figured out.

I think your goals at the track are realistic considering its a vert.

 

Congrats...so the miss was directly attributable to the BRE-spec camshaft? Is this new cam one of LE's Bullet grinds?

 

We came to the conclusion that it was the Comp extreme energy high lift lobe #3192 that was either floating or bouncing the intake valves. It took ~150# of seat pressure to control those valves but I was not comfy with those pressures on a cast cam.

Lloyd swapped out my Comp LE1.5 cam and provided a new LE1 (billet) cam which arrived in the bullet box. Even this cam is not very big compared to the LE2, CC306, 847 etc. , but the improved torque all the way across the curve is a great deal better than the old LE1.5 cam. BLM's are much more in check and the street manners are more friendly with the new cam.

Here is the before and after dyno overlay showing the old LE1.5 cam vs. the new LE1 cam:


The chart speaks for itself.

 

those are some awesome numbers dude! that is exactly what im looking to do over the winter with the le2 heads and le1 cam so those numbers really make me more eager to get the build started

 

That was a 228/235 .560/560 109 LSA cam using some of the new Bullet assymmetrical lobes. It is VERY drivable and makes some pretty good power also.

The seat to seat timing is not too high and don't let the "@ .050" duration #'s fool ya on how much low end it has. The mid range and top end power feels very good on this cam also.

Seems to have a VERY broad powerband in the cars it has been used in.

Lloyd

 

Here is the video

 

Nice #s! Good to hear that everythings working like it should. Anybody know how these #s compare to SAE correct dynojet #s?

 

Superflow numbers SAE corrected:
395 RWHP SAE
348 RWTQ SAE

From what I have seen, Dynojet torque numbers are usually a good bit higher. All of these numbers are on Superflow SF-840 dyno. When I dyno tuned on the dynojet, I made 354 torque and that was on the old cam. I would speculate that if these pulls were made on the same Dynojet, I would have made ~365-370 RWTQ or so.

Clearly not all dynos are the same. Not going to open that can of worms.