GTO1 Posted May 12, 2011 Report Share Posted May 12, 2011 (edited) Finally got the new build running and got some initial dyno numbers. The baseline numbers 489.29 rwhp 475.52 rwtq I think once the motors broken in and the rings seat we'll get that 500 rwhp with our next round of tuning. This build really started a year ago when I had Tony Mamo of AFR port my AFR 205s and my Fast 90. It ended temporarily in August when I started blowing smoke out my tailpipes during the Ames Performance Pontiac Nationals. A leak-down test found that the #8 ring was bad and #3 wasn’t too far behind. The thing was, the results that I had gotten on the track were showing that the work Tony had done for me would have easily put me in the 11.2s or better with better DA in the fall. My PB to-date had been 11.49. So I came down to two options, repair my LS1 stock bottom and get to see the results of Tony’s work as originally intended or go to bigger cubes. Then I realized that I could do both. After searching, I couldn’t find very much posted on AFR 205s on large cubes, specifically on a 427. So that’s what I decided to do, max out the 205s and put Tony’s work to a really “big” test. I selected an ERL 427 LS2 short block as the new base to build on. That was the easy part of the build selection. To do this right, however, I knew that I was going to have to have the right cam. I decided to go to Ed Curtis to find the right stick to pull together the marriage of the larger cubes with what many would now say would be undersized heads. Another thing working against me is that my entire setup was built for the LS1 block and now these components that had work very well for me in the past would restrict both the intake and exhaust. The question is just how much … hopefully it won’t take too long to find that out. I do know two things, regardless of the outcome this build will be the slowest my 427 will ever run and that my 11.49 PB will be history. The build was done by Rich and Erik Johnson of BackStreet Performance. Here’s what I’m working with from last year’s head work • AFR 205 head milled to 61 cc and ported by Tony Mamo • 2.020 and 1.600 lightweight REV valves • PAC Racing 1221 springs installed 155 on seat • Morel Hydraulic Roller lifters (5206) • YellaTerra Roller Rockers The rest includes • Kooks 1 ¾ Headers with catted mids • Borla dual exit exhaust 2.25 pipes • Svede OTRCAI • 90mm Nick William TB • 90mm Fast Intake ported by Tony Mamo • Fast LS1 fuel rails • Lingenfelter High Flow fuel Pump • SLP underdrive pully • Katech Belt tensioner • Meziere Electric Water Pump • MSD LS1 Blaster Coils • Magnecor 8.5 ignition wires • 42 lb flow matched injectors • Manley LS2 double timing set • Melling oil pump • Precision Industries Vigilante Converter (3200 triple disk) • Rossler Terminator II Transmission • Meziere flexplate • Diff Technics 3.73 gears • Harrop Diff cover • Derale Atomic Cool Transmission Cooler The AFR 205s, as ported by Tony, produced the following flow numbers. Based on other flow numbers I’ve seen, they compare to the intake numbers of an AFR 215 and the exhaust numbers of a AFR 225. ...that's on the 3.9 bore, on the 4.125 they'll be higher. Intake .200....154 .300....216 .400....268 .500....296 .550....305 .600....302 Exhaust .200....132 .300....190 .400....222 .500....238 .600....247 http://i2.photobucket.com/albums/y26/GTO1/2006_1201Russell205s0003.jpg The short block is a 427 ERL dry sleeved LS2. Compression will be 11.5:1 The engine components and specs are shown below http://i2.photobucket.com/albums/y26/GTO1/IMG_0840.jpg http://i2.photobucket.com/albums/y26/GTO1/IMG_0837.jpg And finally the FlowTech Induction cam. Ed asked me not to published the specs for this cam so I’ll have to see if he comments. For now I can tell you this its his MAX-AIR 16 spec on a Lunati stick. The power band is “roughly” 3000 to 6200 for 400-427 CID. A requirement was being able to pass emissions testing so its not an overly crazy grind, mid size duration with a high lift. The heads were sent out to be cleaned and tested for leaks just to make sure there was no damage done last year. The results were that they are as good as the day I received them from Tony. Just as clean now too. The lifters were sent to Ed Morel for inspection and they also came back with his good to go. As for the results, the first very impressive thing that we saw was the increase in throttle response. Now I know what Tony meant when he said we'd see it with the smaller heads on these cubes. Its very obvious now that the analog RPM readout on the dash can't keep up with what the motors actually doing. Start up video http://i2.photobucket.com/albums/y26/GTO1/Videos/GTO1427/th_MVI_0854.jpg Once we got on the dyno we had to toss the Jamesbiz dipstick handle and go back to the stock handle to keep oil from blowing out the dipstick. Other then that things went pretty well. Dyno Video http://i2.photobucket.com/albums/y26/GTO1/Videos/GTO1427/th_MVI_0866.jpg Pretty much ran with last years tune. Erik didn't have to do much to the tune to get her going other than the adjustment for the larger injectors and as you can see between the two run in the dyno graph we took away some fuel up top. That little adjustment up top gave us 9 more at the wheels. The car ran perfectly with Ed's new cam ... we were totally surprised. We thought there was going to be some major tuning required to dial it in. What we did expect was the smaller heads choking her at 6000 ... but the cam's power range is only to 6200 so we're pretty much right back at the original stock readline as opposed to the 7000 I ran last year....And I think that's a good thing. lol http://i2.photobucket.com/albums/y26/GTO1/IMG_0870.jpg Edited May 14, 2011 by GTO1 Quote Link to comment Share on other sites More sharing options...
SlowC6 Posted May 12, 2011 Report Share Posted May 12, 2011 awsome build man Quote Link to comment Share on other sites More sharing options...
Archie Posted May 13, 2011 Report Share Posted May 13, 2011 Bad ass build! You ever consider putting some bigger headers on there? Might give you some better numbers especially since you got some big cubes and nice heads on there. Quote Link to comment Share on other sites More sharing options...
GTO1 Posted May 13, 2011 Author Report Share Posted May 13, 2011 Bad ass build! You ever consider putting some bigger headers on there? Might give you some better numbers especially since you got some big cubes and nice heads on there. I will at some point. This is basicly my LS1 build sitting on a 427. I plan on going bigger on both the intake and exhaust side at some point but a cage is next on the list of things to do. Quote Link to comment Share on other sites More sharing options...
GTO1 Posted May 13, 2011 Author Report Share Posted May 13, 2011 Erik did a little more tuning today before I picked up the car. The fall off isn't as bad at 6000 rpm now. Here's a chart showing the gains from the 427 block over my LS1 block. http://i2.photobucket.com/albums/y26/GTO1/LS1vs427.jpg Quote Link to comment Share on other sites More sharing options...
TurboGoKart Posted May 13, 2011 Report Share Posted May 13, 2011 Great build!! Is it typical to have that small of a HP gain going from the 350 to the 427? But as stated earlier, 1 7/8" headers will for sure bump that up given the cubes. That and of course the TB/intake mani, but yeah, that's a major price tag upgrading both of those. Another question, when all this was on the LS1, what cam were you running, and was it a stock bottom end? I'm a little new to the LSX world, and just trying to learn what I can! Thanks! Quote Link to comment Share on other sites More sharing options...
GTO1 Posted May 13, 2011 Author Report Share Posted May 13, 2011 Great build!! What short block did this start out as? Aluminum? Forgive my noob-ness, I'm a little new to the LSX world. Just tryin to learn what I can! Is it typical to have that small of a HP gain going from the 350 to the 427? But as stated earlier, 1 7/8" headers will for sure bump that up given the cubes. This was a LS2 that ERL dry sleeved. The LS1 was a stock bottom. The LS1 cam was 227 230 .613 .591 113+2 The 205 heads are what limited the peak RWHP gain and what causes the motor to run out of air flow at 6000 ... but if you look at the comparison there's actually a 65-75 RWHP gain along most of the curve. Quote Link to comment Share on other sites More sharing options...
coltboostin Posted May 13, 2011 Report Share Posted May 13, 2011 Awesome work! And Backstreet is probably the best little known LS shop in the country. If people only knew the cars that Eric has tuned.... Quote Link to comment Share on other sites More sharing options...
GTO1 Posted May 14, 2011 Author Report Share Posted May 14, 2011 Awesome work! And Backstreet is probably the best little known LS shop in the country. If people only knew the cars that Eric has tuned.... Ran 11.218 @ 119.96 1.589 today off idle... there's a lot more in her. Rich and Eric don't get the PR they deserve. Seems like every time a car they do that gets national attention ... the fact that Backstreet did the work always seems to get left out of the article. Quote Link to comment Share on other sites More sharing options...
coltboostin Posted May 14, 2011 Report Share Posted May 14, 2011 Ran 11.218 @ 119.96 1.589 today off idle... there's a lot more in her. Rich and Eric don't get the PR they deserve. Seems like every time a car they do that gets national attention ... the fact that Backstreet did the work always seems to get left out of the article. I have told Eric for a while to just make a VIDEO blog or something of the sort. He has no interest. If people saw the cars that came out of that shop-and they had the desire to expand, they'd be bigger than Lingenfelter. Quote Link to comment Share on other sites More sharing options...
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