Minagera Posted August 22, 2008 Report Share Posted August 22, 2008 (edited) Hey all, Most of you know who I am, even more now that I actually made an appearance at PF08. Anyway this is the Engine and Performance Mods forum, so lets get to it. I happen to have a block at the house that is already bored 20 over, .50 mm, that still has good cylinder walls. I also happen to have a set of 20 over, .50mm, flat top Clevite Cast pistons. http://minagera.org/gallery/d/1302-2/IMG_1875.JPG http://minagera.org/gallery/d/1306-1/IMG_1876.JPG So being that they are flat tops they should bump up my compression by one point. So 8:1 on a conquest with cast pistons and a 14g(maybe 14b) turbo. A little more low end and off the line power and should get better economy because they engine will be making more power without the added cfm from the turbo. (<that sentence = less gas used) Oh and what build would be complete without helpers. http://minagera.org/gallery/d/1318-1/IMG_1880.JPG I will get more pictures up as I rebuild this engine. I will also put together a cost breakdown on what I am calling a budget build. Cheers, Matt Edited August 22, 2008 by Minagera Link to comment Share on other sites More sharing options...
Funky Phil Posted August 22, 2008 Report Share Posted August 22, 2008 So being that they are flat tops they should bump up my compression by one point. So 8:1 on a conquest with cast pistons and a 14g(maybe 14b) Umm more like 8:5.1. Watch your timing and get a wideband. Good luck! phil Link to comment Share on other sites More sharing options...
Minagera Posted August 22, 2008 Author Report Share Posted August 22, 2008 Umm more like 8:5.1. Watch your timing and get a wideband. Good luck! phil Really? Either way not too worried about it. Might MPI this engine, but probably will be a TBI. It will have a wideband, but it will be stock timing. Link to comment Share on other sites More sharing options...
Komeuppance Posted August 22, 2008 Report Share Posted August 22, 2008 Worth a shot. If anything, it's for "research" purposes. -Robert Link to comment Share on other sites More sharing options...
Minagera Posted August 22, 2008 Author Report Share Posted August 22, 2008 Worth a shot. If anything, it's for "research" purposes. -Robert Exactly. I look at it this way. DSM guys take 2gen pistons and 1gen rods and that bumps their compression from 7.8 to 8.5 to 1 and they do 350-400 WHP on that setup all day long... Compression and turbo engines isn't the devil, it just needs to be watched carefully. :-) Link to comment Share on other sites More sharing options...
jonboyb Posted August 22, 2008 Report Share Posted August 22, 2008 My race engine has specifically designed Ross 8.5:1 pistons. They have a 2mm center dome but significant eyebrow relief for the valves due to my cam specs. Depending on your deck height and chamber cc, I would guess those flat-tops to be 8.3-8.4:1. Certainly over 8:1. Link to comment Share on other sites More sharing options...
shift1313 Posted August 22, 2008 Report Share Posted August 22, 2008 i agree with jonboy. i think 6cc dish with the stock pin height is 8:1. stock 7:1 i think is 16cc dish or somewhere in that range. good luck with the project. Link to comment Share on other sites More sharing options...
BlowinUp54B's Posted August 23, 2008 Report Share Posted August 23, 2008 Good luck with the project when will it be done? Can't wait because we need some meets in H-ville. Link to comment Share on other sites More sharing options...
Funky Phil Posted August 23, 2008 Report Share Posted August 23, 2008 Im not saying it cant be done or shouldnt. I was very close to building a flattop setup but need to finish another project. But going into any build without knowing what your playing with is a recipe I dont choose to taste. Once again, Good Luck phil Link to comment Share on other sites More sharing options...
Minagera Posted August 23, 2008 Author Report Share Posted August 23, 2008 Im not saying it cant be done or shouldnt. I was very close to building a flattop setup but need to finish another project. But going into any build without knowing what your playing with is a recipe I dont choose to taste. Once again, Good Luck phil I hear ya man. I will try to keep everyone up to date on this build. Who knows might blow up in my face. Link to comment Share on other sites More sharing options...
jahjah Posted August 23, 2008 Report Share Posted August 23, 2008 (edited) I run flat top pistons and regularly do 18 psi with a 17c on an MPI, my compression is like 8.6:1 or so. Tune it carefuly and you'll enjoy it My car comes alive like a V8 Edited August 23, 2008 by jahjah Link to comment Share on other sites More sharing options...
Minagera Posted August 23, 2008 Author Report Share Posted August 23, 2008 I run flat top pistons and regularly do 18 psi with a 17c on an MPI, my compression is like 8.6:1 or so. Tune it carefuly and you'll enjoy it My car comes alive like a V8 Good to know! Link to comment Share on other sites More sharing options...
shoquest2007 Posted August 23, 2008 Report Share Posted August 23, 2008 Been running the flat tops that you bought same ones, and we have been pushing 15 PSI on it with the 62-1 with the FIP computer and havent had any problems with the internals yet. Just a broken oil inlet line for the turbo which trashed the bearings and shaft in the turbo, so i am rebuilding that , but it was nice to be able to change the map and be able to drive NA and still get somewhere. Let me know how you do. As for timing, We are still very close to stock timing I think at 9 to 9.5 We are also using E85 for fuel. Got too much pinging out of the 93 gas. Link to comment Share on other sites More sharing options...
Minagera Posted September 21, 2008 Author Report Share Posted September 21, 2008 Well put it all together tonight and fired it back up. Cranked fine. Good oil pressure, and damn strong exhaust. Retorqueing tomorrow and then breaking in those rings. Pics will be up tomorrow... Link to comment Share on other sites More sharing options...
Minagera Posted October 4, 2008 Author Report Share Posted October 4, 2008 http://minagera.org/gallery/d/4794-1/P9190142.JPG http://minagera.org/gallery/d/4797-1/P9190143.JPG http://minagera.org/gallery/d/4806-1/P9190147.JPG http://minagera.org/gallery/d/4812-1/P9190150.JPG http://minagera.org/gallery/d/4818-1/P9190152.JPG http://minagera.org/gallery/d/4824-1/P9190154.JPG Notice the picture, the pistons are sitting above the deck height. Link to comment Share on other sites More sharing options...
Dave-O Posted October 4, 2008 Report Share Posted October 4, 2008 Very nice. Is that an FD Rx7 behind you in that 5th pic? Only Rx7 I haven't owned yet, rofl. Link to comment Share on other sites More sharing options...
JamesR Posted October 5, 2008 Report Share Posted October 5, 2008 Very nice. Is that an FD Rx7 behind you in that 5th pic? Only Rx7 I haven't owned yet, rofl. check his sig. Link to comment Share on other sites More sharing options...
Tim_C. Posted December 19, 2008 Report Share Posted December 19, 2008 The flat top set-up with factory N/A replacement pistons is more like 9:1 static ratio. The key is the pin height is shorter which makes for much more compression. Can't compare to the 2.0L. This engine has a much longer stroke which requires more perfect tuning. Point being the detonation is much more severe because it has more distance to travel into the detonation. IMHO MPI is required and very precise tuning to run much over 12 PSI. However, it depends on how cool you can get the intake charge. A large turbo with a big intercooler will have cooler temps to be a bit safer. Link to comment Share on other sites More sharing options...
jahjah Posted December 20, 2008 Report Share Posted December 20, 2008 9:1 really? hmmm.... spiffy Link to comment Share on other sites More sharing options...
Tim_C. Posted December 28, 2008 Report Share Posted December 28, 2008 Yes, I was getting 137 PSI compression at 6000' altitude. That is the same as other engines we tested that are 9:1 static compression ratio OEM. Link to comment Share on other sites More sharing options...
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