The 3 Day Swap, from '81 Volvo Wagon to Tire Slaying Daily
07-23-2015, 10:58 AM
#242
Well the results are in 300whp 300tq 
Here is how it went down. I had previously dyno'd at CPS with the bench tune from PSI Conversions and made 250whp 300tq. I was happy with that on a 100% stock engine and bench tune but figured there was some more in it. With the cam I chose, there were plenty of dyno's with 5.3s making 325whp+ and a bunch of LS1 cars making 380whp+. I figured it would make right at 325whp or so. We got on the rollers and were able to get the idle dialed in and sort out the driveability stuff. The time came and we made the first pull, 300/300 BAM! I was floored! 50whp right off the rip! Confident there was more to be had, I was anxious to see what it was going to make as we began to fiddle. I though for sure there is another 25whp left in the tune. Changes are flashed and another pull, 300/300. Didn't respond to the changes, huh? We added fuel, pulled timing, nothing made a change. All said and done the best pull was 305/299.85
Needless to say, I was a bit deflated when we went for a drive to check VSS against GPS and see how it was in the real world off the dyno. It feels mostly like stock until you get to 4K rpms. Then the cam starts working and WOW does it run to 6K. We get back to the shop and I was in a better place but still scratching my head as to why the numbers were so damn low. Looking at the graph I am limiting the engine somewhere. Intake, head flow, exhaust. Somewhere in there is a bottleneck. I know the heads would make a considerable difference, but my gut tells me the LS1 intake manifold is a huge restriction. Also if you look at the curve, the only place the new cam over performs the old cam is above 4250rpms. I was expecting to see a bigger gain over the stock cam throughout the entire curve, am I wrong in my thinking? The last car I dyno'd I had no baseline curve to compare against so I wasn't looking for the difference throughout the curve. I just can't see how my numbers are so low considering all of the dyno sheets and posts I have looked at over the past few weeks. It was VERY hot outside yesterday, 98* 110* heat index or so. I know that isn't helping matters and even the tuner said on a cold day it should dyno 15whp or higher.
Ok, so now that I have rambled about my disappointment, lets get onto the good parts of the little overhaul this past weekend.
The brakes, oh my the BRAKES!!!!! These things are unreal. After bedding in the rotors and pads Tuesday night I went for a cruise to get some miles on the cam so I could change the oil prior to the dyno. Decided after a long stretch on the highway I would hit the brakes with some meaning on the ramp if I had the room. I did and after I peeled my face of the windshield I just started to giggle. They work, they work very well.
Under the hood is cleaner, which makes me happy. The tune is speed density, which was something I had considered so I could ditch the MAF and the extra wiring. Now I can make the intake cleaner, lighter and easier to route. I will work on getting the filter further behind the headlight and with far less clamps and couplers. I am now motivated to address the rust on the battery tray and adding back power steering.
Overall I can't complain with the recent additions to the car. It has become more drivable with the brakes and the horsepower, a bit more refined with the speedo working and the under hood appearance changes, and it has more presence with the idle. It chops, but it isn't in your face. I think with the addition of a resonator/muffler to quiet the drone a bit and tone it down some it will be barely noticeable but there if you are looking for it.
Here is how it went down. I had previously dyno'd at CPS with the bench tune from PSI Conversions and made 250whp 300tq. I was happy with that on a 100% stock engine and bench tune but figured there was some more in it. With the cam I chose, there were plenty of dyno's with 5.3s making 325whp+ and a bunch of LS1 cars making 380whp+. I figured it would make right at 325whp or so. We got on the rollers and were able to get the idle dialed in and sort out the driveability stuff. The time came and we made the first pull, 300/300 BAM! I was floored! 50whp right off the rip! Confident there was more to be had, I was anxious to see what it was going to make as we began to fiddle. I though for sure there is another 25whp left in the tune. Changes are flashed and another pull, 300/300. Didn't respond to the changes, huh? We added fuel, pulled timing, nothing made a change. All said and done the best pull was 305/299.85
Needless to say, I was a bit deflated when we went for a drive to check VSS against GPS and see how it was in the real world off the dyno. It feels mostly like stock until you get to 4K rpms. Then the cam starts working and WOW does it run to 6K. We get back to the shop and I was in a better place but still scratching my head as to why the numbers were so damn low. Looking at the graph I am limiting the engine somewhere. Intake, head flow, exhaust. Somewhere in there is a bottleneck. I know the heads would make a considerable difference, but my gut tells me the LS1 intake manifold is a huge restriction. Also if you look at the curve, the only place the new cam over performs the old cam is above 4250rpms. I was expecting to see a bigger gain over the stock cam throughout the entire curve, am I wrong in my thinking? The last car I dyno'd I had no baseline curve to compare against so I wasn't looking for the difference throughout the curve. I just can't see how my numbers are so low considering all of the dyno sheets and posts I have looked at over the past few weeks. It was VERY hot outside yesterday, 98* 110* heat index or so. I know that isn't helping matters and even the tuner said on a cold day it should dyno 15whp or higher.
Ok, so now that I have rambled about my disappointment, lets get onto the good parts of the little overhaul this past weekend.
The brakes, oh my the BRAKES!!!!! These things are unreal. After bedding in the rotors and pads Tuesday night I went for a cruise to get some miles on the cam so I could change the oil prior to the dyno. Decided after a long stretch on the highway I would hit the brakes with some meaning on the ramp if I had the room. I did and after I peeled my face of the windshield I just started to giggle. They work, they work very well.
Under the hood is cleaner, which makes me happy. The tune is speed density, which was something I had considered so I could ditch the MAF and the extra wiring. Now I can make the intake cleaner, lighter and easier to route. I will work on getting the filter further behind the headlight and with far less clamps and couplers. I am now motivated to address the rust on the battery tray and adding back power steering.
Overall I can't complain with the recent additions to the car. It has become more drivable with the brakes and the horsepower, a bit more refined with the speedo working and the under hood appearance changes, and it has more presence with the idle. It chops, but it isn't in your face. I think with the addition of a resonator/muffler to quiet the drone a bit and tone it down some it will be barely noticeable but there if you are looking for it.
07-23-2015, 05:02 PM
#243
I don't recall what your exhaust setup looked like and the pictures you posted in 2013 aren't showing anymore. Aside from any exhaust restriction, I would say it's probably your head flow that is holding your numbers around 300hp. Time to whip out the dremel and a case of sanding bits! The LS1 intake should support over 300hp.
07-27-2015, 10:36 AM
#245
So there was a break in the heat this weekend and just in time for a cruise with some friends down to Beaufort for a meet of sorts. The ride back we were seeing mid 70* IAT and I think the dyno numbers aren't even close. This thing pulls hard, I buried the speedo more than a few times on the way back. Ran down to Mexico for some burritos and got some video of the car. You can see the speedo, which is within 1 mph accurate to GPS.
08-10-2015, 01:21 AM
#248
So how long did your 3 day swap actually take?
08-11-2015, 09:16 PM
#250
