Adam Posted June 17, 2020 Share Posted June 17, 2020 (edited) Thank you all for the welcomes and positive responses in the new members section. http://www.mkivsupra.net/vbb/showthread.php?358516-Hello-from-Wiltshire I’m quite dislexic so I seriously hope I don't come across as being dumb and arrogant. I’ve read quite a few forums recently and many people who attempt the NA-T conversions of GE blocks get questioned “why not go GTE in the first place?”. Based on my assumptions I’m hoping this will be an irrelevant part of this journey. I really enjoy dismantling, labeling, cleaning, inspecting and making improvements etc. This all leads up to preparing for a nice clean build to which I really enjoy. You get to see your clean components ready to go back together. So I would be spending £3.5k to £4k on a GTE engine that would be broken down to the core for two oil feed lines and six oil squirters? Please do chime in with, “You’re wrong…” if I am mistaken. The Target… Time for me to learn, I’ll be asking a ton of questions throughout this build. I’ll also share my findings to help others on the way. Engine expectations: (I know there are so many variables here). Mainly a weekend car with yearly track days, drag strips and a tiny bit of drifting. Good low power drivability around town would be nice. I would like 500hp to 600hp with a 15% to 20% overhead for stressed components with good long term reliability in mind running standard VVTi cams? Also, I don’t mind too much turbo lag. Am I being to conservitave as we have seven main journals? The standard inlet manifold wont be used, it’s ugly… Work to be done on the GE Block and possibilities. I’m gifted with the VVTi head so the rods and pistons need out. Honing for the new rings and pistons will be a must and line boring if required. I would like to use the BC PROH2K rods with CP pistons with no modifications to the crank. A Fluidampr pulley will be fitted later on in the build, hoping I won't need the rotating assembly to be balanced. I’m not aiming for really high RPM just yet. Compression ratio combinations with the hope of retaining a non interference engine. If I were to go for pistons with a compression ratio of 8.5 to 1 what head gasket thickness has everyone gone for? I really don't want any “Detting”. Side note assumptions, correct any stupidity... 1, With no oil squirters and running a GTE oil pump. I’ll have better oil pressure overheads with the expense of piston cooling, is this going to be ok for 500+bhp? 2, Log manifold for a compact engine bay and reduced spool times at the expense of volumetric efficiency? 3, Tee’d and fully supported ridged stainless steel oil feed line with SS flexible braided ptfe lined end fitting for the turbo. Pictures to follow... Edited June 17, 2020 by Adam Spelling, it's always the spelling... (see edit history) Quote Link to comment Share on other sites More sharing options...
bluecoupe46 Posted June 17, 2020 Share Posted June 17, 2020 Welcome to the forum! It sounds like you've got most of it covered. Log manifolds are great for spool times and keep heat in rather than spreading it round the bay. In terms of headgasket. Use the stock GTE headgasket to reduce your compression ratio down to 8:5.1 With the right turbo, fueling and ecu you'll see 500 easily enough, and likely 600 if you upscale everything. I'd recommend switching to a walbro 450lph fuel pump, change to an aftermarket top feed fuel rail with 600+cc injectors. You'll want to bypass the stock fuel damper, so you'll want to get some lengths of aftermarket braided fuel line. I can help you with sizes. Otherwise whifbitz sell a kit, but it's expensive for what you get (I went the whifbitz route, but now I've got the kit I can see what's included and the sizing of the lines etc...). Im doing similar to you in my track car. Currently got 2 major projects on the go. 750hp 2jz gte for my fully refreshed supra, and a 2jz ge (NA-T) for my BMW e36 track car. If you need any help or advice give me a shout. Kind regards, Alex Quote Link to comment Share on other sites More sharing options...
Noz Posted June 17, 2020 Share Posted June 17, 2020 GTE headgasket takes it to 9:1. Piston dish is different so it won't drop fully to 8.5 Quote Link to comment Share on other sites More sharing options...
bluecoupe46 Posted June 17, 2020 Share Posted June 17, 2020 GTE headgasket takes it to 9:1. Piston dish is different so it won't drop fully to 8.5Fair enough. I knew the piston dish between the gte and ge was different, wasn't sure how different though. I heard the gte headgasket took the engine to 8:5.1 but must've been misinformation. In that case, a set of gte pistons or aftermarket 8:5.1 gte pistons will do you fine. Quote Link to comment Share on other sites More sharing options...
P_Bazz Posted June 17, 2020 Share Posted June 17, 2020 The NA head is better suited to the NA headgasket because of the squish, if you're building the bottom end anyway I would reduce the compression ratio with the pistons rather than the headgasket. The squish with a TT headgasket is around 2mm which is more than ideal and will negatively impact combustion of the fuel. Quote Link to comment Share on other sites More sharing options...
Noz Posted June 17, 2020 Share Posted June 17, 2020 Fair enough. I knew the piston dish between the gte and ge was different, wasn't sure how different though. I heard the gte headgasket took the engine to 8:5.1 but must've been misinformation. In that case, a set of gte pistons or aftermarket 8:5.1 gte pistons will do you fine. /QUOTE] Why use GTE pistons? GE pistons are the same material and my GE pistons are fine at 600hp Quote Link to comment Share on other sites More sharing options...
bluecoupe46 Posted June 17, 2020 Share Posted June 17, 2020 Why use GTE pistons? GE pistons are the same material and my GE pistons are fine at 600hpYou literally just said with GE pistons the compression ratio is 9:0.1 not 8:5.1 the op wants 8:5.1. Hence why I said use gte pistons. Can use 9:0.1 pistons fine, my Manley pistons in my 800hp gte build are 9:0.1. I won't be changing the GE pistons in my 400hp track car build either. Just the op specifically stated 8:5.1 Quote Link to comment Share on other sites More sharing options...
Adam Posted June 17, 2020 Author Share Posted June 17, 2020 Hi all, This is exactly the discussion I need to clarify before buying anything, I really appreciate the comments. A few questions and comments, 1, What's the best compression ratio for safe boost at 500 to 600bhp 2, I thought GE pistons created a ratio of 10.5:1 for NA use? 3, The thinker GTE head gasket is there for strength if anything and maybe also helps to lower the compression ratio? 4, I’m not sure I would want to use an OEM GE head gasket under any boost conditions. 5, If I get 8.5:1 CP pistons and use an OEM GTE gasket I’ll be further reducing the compression ratio? - Might need to ask CP and get back to you guys with the info. 6, If the above “5” is the case. I’ll need a higher piston comp ratio to compensate for a stronger and thicker head gasket? Quote Link to comment Share on other sites More sharing options...
AC93 Posted June 17, 2020 Share Posted June 17, 2020 What gearbox are you using? Quote Link to comment Share on other sites More sharing options...
Noz Posted June 17, 2020 Share Posted June 17, 2020 (edited) You literally just said with GE pistons the compression ratio is 9:0.1 not 8:5.1 the op wants 8:5.1. Hence why I said use gte pistons. Can use 9:0.1 pistons fine, my Manley pistons in my 800hp gte build are 9:0.1. I won't be changing the GE pistons in my 400hp track car build either. Just the op specifically stated 8:5.1 /QUOTE] My bad sorry. I missed that. No idea why someone would want 8.5 unless they were tuninf it themselves and wanted safety factor. 1. 9.1 is fine. 2. 10.1. When used with NA HG. You suggested using a GTE HG. 3. The thickness is to adjust compression ratio of the engine. A thicker gasket isn't a stronger one. Vs the NA one its just as strong. However you don't want a 10.1 compression ratio at 600hp 4. Upto 450hp GE gasket will be fine. Its your compression ratio that begins to be important. You don't want boost at 10.1 on an NA setup. 5. Upto 600hp just needs head studs and GTE gasket. Only need to do an engine tear if somethings going wrong. I run 600hp. I have low compression 140s on two cylinders so thinking to rebuild. But for me, its a wear and tear situation I think. 400hp can use a w58 trans and unopened engine. 500hp needs different transmission and ideally needs GTE HG. The spec for 500 to 600 is minimal. But 500. Is a big jump from 400. Mainly due to w58 being too weak if your manual and GTE HG with ARP headstuds. Edited June 17, 2020 by Noz (see edit history) Quote Link to comment Share on other sites More sharing options...
Adam Posted June 17, 2020 Author Share Posted June 17, 2020 Hi Noz, Thanks for the info and advice. Ok, if I go with CP pistons with a compression of 9.0:1 with BC rods, OEM GTE HG on a GE block. I’ll be safe with enough overheads and this setup could take more in the future? I’ll after a CD009 when the engine is finished. This will be quite a bit later on in the build though. Quote Link to comment Share on other sites More sharing options...
Noz Posted June 18, 2020 Share Posted June 18, 2020 Hi Noz, Thanks for the info and advice. Ok, if I go with CP pistons with a compression of 9.0:1 with BC rods, OEM GTE HG on a GE block. I’ll be safe with enough overheads and this setup could take more in the future? I’ll after a CD009 when the engine is finished. This will be quite a bit later on in the build though. 600 is the most i think anyone should go for with a stock bottom end. Do your research mate. There are plenty of builds at 600. Not many after. So i wouldn't. Quote Link to comment Share on other sites More sharing options...
Adam Posted June 18, 2020 Author Share Posted June 18, 2020 Thanks Noz, I found this very helpful, Calculate Your Compression Ratio Quote Link to comment Share on other sites More sharing options...
Style Posted June 19, 2020 Share Posted June 19, 2020 I had a bit of a nightmare selecting pistons and headgasket for my build (non-VVTi GE) as information is a bit vague and there is some conflicting data, but maybe I was being overly anal about it. Aftermarket pistons usually state the compression ratio that they would give on a GTE engine. So if you were to fit "9.0:1" pistons along with a GTE headgasket to a non-VVTi GE, you'd probably be closer to 8.5:1. You mentioned that you have a VVTi head which may help bump that back up towards 9.0:1 again but I'm honestly not sure where the 0.5:1 difference between the VVTi and non-VVTi GE's come from (the stock pistons, head or a combo of both). So basically I've had a bit of a ramble but think you'll be anywhere in the region of what you want and okay anyway I built a non-VVTi engine up with a GTE headgasket and some "9.0:1" Manley pistons but with a lightly skimmed deck so I THINK I'm in the ball park of 9.0:1 as opposed to 8.5:1. Only way to know for sure would be to fluid fill the chamber at TDC and do the calcs. But I've decided to just run with it as it's overbuilt for my power goals Quote Link to comment Share on other sites More sharing options...
Cillian bolger Posted August 22, 2021 Share Posted August 22, 2021 Anyone know what the right Compression for gs300 2jz I have just picked one up cheap and want to find out thanks again Quote Link to comment Share on other sites More sharing options...
Noz Posted August 23, 2021 Share Posted August 23, 2021 Aiming for 170 isn't a bad shout. I think the min spec is like 150 something. Quote Link to comment Share on other sites More sharing options...
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