After tweaking the MAFT and ATAP-ing I went to Turbo Technology and re-dynoed the LS1 with the new B1 cam, LS6 intake and ASP crank pulley and picked up 31RWHP and 3RWTQ <img src="gr_images/icons/cool.gif" border="0"> That's right...it's not a misprint only 3 more ft/lbs of peak TQ! My new total numbers are 331RWHP/318RWTQ vs. the previous stock set-up at 300RWHP/315RWTQ.

My '99 motor still has the stock exhaust manifolds and CATs so I felt that this was a reasonable increase in HP but was really amazed at the torque numbers, especially since the combination of LS6 intake & B1 cam appears to have actually decreased the torque curve below 4700RPM and increased torque significantly between 4700 & 6000 RPM (right where I want it <img src="gr_grin.gif" border="0"> ). The actual peak HP number now is at 6200RPM (vs. 5400 stock) when I hit the rev limiter. You can see by the graph below how much power is added up top:

 

Don't worry 3#/ft of tq is about the normal gain for an MTI cam.


<img src="gr_images/icons/wink.gif" border="0">

 

Whatever Terry, it has more to do with the stock exhaust manifolds vs headers when it comes to torque.

You picked up a LOT more than "31 rwhp" with those mods. Don't compare peak values, look at all that area under the racing rpm range curve! This new combo will be MUCH quicker at the track.

Now, get some headers!

Tony

 

Put some LT's on the car and thats where you will see the #'s jump

 

You definately have about 35 rwhp left in that setup with a good set of Longtubes and a good 3 inch offroad y-pipe.


Josh

 

Long tube stepped headers with merge collectors are definitely the next mod along with "X" pipe and true 3" duals. Since I have to fabricate my own headers to fit my G-body chassis anyway I figured that I might as well do something a little trick <img src="gr_images/icons/wink.gif" border="0">

Of course no one has posted a good site yet to one of my last posts asking for anyplace that offers real merge collectors at a "decent" price <img src="graemlins/gr_cry.gif" border="0" alt="[whiner]" />

I still can't believe only 318 peak on the torque though <img src="images/icons/confused.gif" border="0"> I have never seen a modified (header-less) LS1 with this low of a torque rating. I wonder if my current true duals with stock CATs actually cost low end torque over the F-body "y-pipe" set-up?

It's funny though, you'd never know the torque is so low because now it just annihilates the tires in 1st gear like its on wet pavement (even more so than before!) <img src="gr_grin.gif" border="0">

 

That's interesting. Headers. <img src="graemlins/gr_chug.gif" border="0" alt="[chug]" />

 

[quote]Originally posted by Nine Ball:
<strong>Whatever Terry, it has more to do with the stock exhaust manifolds vs headers when it comes to torque.

You picked up a LOT more than "31 rwhp" with those mods. Don't compare peak values, look at all that area under the racing rpm range curve! This new combo will be MUCH quicker at the track.

Now, get some headers!

Tony</strong><hr></blockquote>

I totally agree with Tony. A few other guys added B1/T1 cams with stock manifolds and all of them saw very similar gains (~20-25rwhp/less 5rwtq).

About a year ago, my car w/ just the addition of the B1/ported TB went from 337rwhp/335rwtq to 372rwhp/362rwtq. Sure looks like 3lb-ft of torque ti me. <img src="gr_tounge.gif" border="0">


{copy and paste link into address bar to view]

B1 cam dyno

[ January 05, 2002: Message edited by: Jason99T/A ]</p>

 

John, have you test-fit any of the available headers out there for your car? I mean, the Corvette stuff, the F-body stuff, the truck stuff?

Don't go with stepped headers, they will be too big and I guarantee you will be leaving some torque left on the table. I'd only recommend you go with stepped headers if you are planning on a big-cube (422ci) motor in the future. Until then, stick with the 1-3/4" primary longtubes.

Also, I've never seen a 346ci LS1 make more torque than horsepower, so I think you are about right. Sure, some guys show more torque with their A4 converter spikes, but their curves will look like 6-speed (normal) curves with the converter locked up.

And I'd have to say that dual 3" exhaust is very overkill for your motor. dual 2.5" would be plenty.

Tony

[ January 05, 2002: Message edited by: Nine Ball ]</p>

 

Hey Terry,

I have a question. Maybe you have an answer. I have a MTI T1 cam. I guess I don't have much low-end torque? Can you explain how I have the
BEST 60 FT TIME of anyone using the Vig 2800 at 3400+ lbs N/A?

I don't believe ANYONE has beaten by 1.64 short times with the Vig 2800s at my weight and without juice. I pulled 1.64 twice and 1.65 once at Atco three weeks ago. I guess I am down on low-end torque?

 

Tony, I haven't tried any other LS1 headers to see if they'd fit my chassis only because I have been told that on my drivers side the steering column is located too close to the motor to fit "typical" LS1 headers. Of course the only way to verify this would be to buy a set and see if they fit, however, I haven't seen a good set of LT's at a reasonable price until the Hooker's have just came along....I suppose $410 + shipping might not be a bad price to pay and then resell them if they don't fit.

Perhaps I should have also stated that my final mods for this motor will include Stage II 2.055/1.60 heads which hopefully will get me to the 475-490 FWHP range which IMHO necessitates the larger headers and 3" exhaust.

I had a local shop that has several stock class record holders under their belt (e.g., 11.61 out of a stock head/intake & cam lift 305 carb '85 Camaro) come up with the spec's for the headers based on 346 cubes and ~420RWHP peaking at 6300RPM. There 1st recommendation was using a 1-5/8" to 1-3/4" to 1-7/8" step, however, I told them that I did not want more low end torque so they said just skip the 1-5/8" step and use the latter two.

Here is also an interesting link on Breathless's new C5 stepped headers that I'd like to hear your opinion on (not that you'd have one <img src="gr_tounge.gif" border="0"> ) http://www.breathlessperformance.com/108.htm

Here is a quote from Ernie at Breathless regarding trying these headers out on the dyno:
[quote]We just finished testing our long Tube Step Headers on a 2002 Z06. Headers and X-pipe gave us 28.5 RWHP with the gains starting as low as 2800 rpm.
We also did a test on another 2002 with just the Header and picked up 14RWHP at 4500 RPM. We saw gains on just the Header as low as 3000 RPM<hr></blockquote>
Tony, I usually don't question you wisdom on LS1 stuff because Lord knows you have all the credentials under your belt (and an emptier pocket book to prove it!) but I am also convinced that a motor making upwards of almost 500FWHP needs to breathe on the exhaust side for the ultimate performance when running through mufflers. Now people can try to convince me that track results will show that open exhaust vs. closed exhaust nets very little difference and to these people I would say, sometimes, however, it probably just means that your A/F isn't optimized fully for the open exhaust. Just my .02 and experiences from the past at the track <img src="gr_images/icons/wink.gif" border="0"> Thanks again for your input!

 

For those saying these cams wont make tq...

I went from a best bolton dyno of 350/350 to a best after B1 dyno (after removing cats and adding LS6 intake also) to 402/378. The cam swap alone netted 35 rwhp and 13 rwtq! Now if only I could get this new cam to agree with stock tuning... <img src="gr_grin.gif" border="0"> <img src="gr_images/icons/cool.gif" border="0">

 

Oh yeah, raise that rev limiter too! That cam [i]wants[/] to be shifted at 6400-6500, you can feel it begging for more rpms with the stock limiter <img src="gr_grin.gif" border="0">

 

TrahnZam WS6, holy smokes! 402/378 with stock heads?

 

hey John glad to see things are going well. I was tuning the blower car at the Team Dyno day. you ever get those codes killed?

Good luck

 

TwoFast4Lv, hello again! And no, I just added the PO300 code to my previous 5 so now I have 6 total codes to delete if LS1_Edit ever comes out in the single user version <img src="gr_images/icons/mad.gif" border="0">

After reviewing my ATAP logs from the dyno I see more room for improvement though! I was only pulling about 24.3° total timing between 4000-6000RPM, up to 3.6° knock retard and my LTFT's were trying to compensate for an overly lean part throttle by adding as high as 11.7% fuel at WOT. What's strange is that my highest dyno run exhibited all the above symptoms <img src="images/icons/confused.gif" border="0"> No knock retard on the other three pulls (the above run had the MAFT set the leanest at WOT though).

I think this explains some of the missing torque too since I now believe that the PCM acted as though I had a higher load on the motor than was actually there and tried to compensate by pulling back the timing and fattening up the A/F (avg O2's were about 0.917) due to being too lean on part throttle. I'll be fattening up the base fuel now and get the LTFT's back down closer to zero.

[ January 06, 2002: Message edited by: John B ]</p>

 

Get some tuning on that car and you will see how stong the B1 is. I got my PCM done by Ed Wright last week and im completely happy. Car shifts at 6400rpms and revlimiter at 6800 rpms. My WOT timing was 28-30 degrees along with my o2s in the 900 range. I can't compare dyno before and after tuning because they were on different dynos. I'll just say i picked up ALOT of TQ after tuning. Prolly has to do with the PCM getting out of wack adding fuel and pulling fuel.

 

hey get ahold of me I got a friend who may help <img src="gr_images/icons/wink.gif" border="0">

cybergroo@technolust.net

Ellis