hello just lookin for a few pointers/advice really. ive picked up a passat gt,2.0 16v 9a. i want to rebuild this engine with help from my dad and a mechanic m8 of mine. the spec i want to go for is as follows..... rebore to 83.5mm with forged pistons (not sure on c/r? around 11 or 12/1? 92.8mm forged crank,lightened? balanced? knife edged?. forged eurospec 475gram,144mm con rods. arp head/main bearing bolts. steel uprated oil pump/only with solid lifter i think. solid lifter blydenstein original 9a head,ported? maybe stick with hydraulic but with stronger springs and lightweight retainers etc... no idea what cam spec? 280-300 around 12mm lift? baffled sump and windage tray. new 45 webber carbs. motec ignition management (dis wasted spark) nice flames B) . lightened flywheel. all bottom end balanced as one. basically id appreciate any opinions on anything above. the actual engine size? cc's. will the 83.5mm pistons even be ok in this setup? anything at all you can add or advise on would be fantastic! the sort of power/rpm ill be looking at? was gonna go abf with diesel crank but wanna keep my first engine build as simple as poss as far as machining etc... neil. Edited by: riley
Re your DubForce thread (I'm too lazy to register ) the spec i want to go for is as follows..... rebore to 83.5mm with forged pistons (not sure on c/r? GO 11.5:1 - A GOOD BALANCE BETWEEN PERFORMANCE AND PINKING! 92.8mm forged crank,lightened? balanced? knife edged? DEFINATELY DO THIS. HI REV RESPONSE BECOMES SOOOO GOOD, IT'S JUST NOT FUNNY. FEELS LIKE YOU GAIN 30HP WHEN IT'S ONLY ABOUT 10-15. forged 475gram 144mm con rods. OR SHOT PEEN THE STOCK ONES, BUT IF YOU CAN AFFORD IT, GET SOME CUSTOM MADE. arp head/main bearing bolts. SPOT ON steel uprated oil pump. WOULDN'T MIND ONE OF THESE MYSELF - WHO MAKES THEM?! solid lifter blydenstein original 9a head,ported? I STILL USE HYD. LIFTERS, ALTHOUGH THEY WEAR OUT RELATIVELY QUICK WITH HIGHER LIFT CAMS STRESSING THEM OUT. ROBT HAS AN ARROW SLH KIT WHICH HE RECOMMENDED TO ME no idea what cam spec? THIS DEPENDS ON A LOT OF THINGS - WITH THE RIGHT SETUP, EVEN 276'S WILL HOLD POWER TO 8000RPM WITHOUT FEELING LIKE THEY'RE DYING OFF. MY 285S W/ 11.8MM OF LIFT WANT TO GO AND GO BUT IT'S JUST ME PARANOID ABOUT REVS THAT'S STOPPING THEM. MY PEAK POWER IS AT 7,690RPM AND FROM 4,000RPM PERFORMANCE IS REALLY STRONG. THERE'S A STRONG SURGE (AND YOU REALLY FEEL IT) AT 2850RPM AS THE TORQUE BUILDS UP AND IT'S IN FULL SWING AT 5,000RPM (CRACKING THROTTLE RESPONSE!). MY ENGINE IS PERFECTLY STREETABLE BUT DOES USE A BIT OF FUEL IN STOP-START TRAFFIC. baffled sump and windage tray: SCHRICK ONE IS STILL AROUND FOR BIG MONEY I THINK - MINE'S STOCK STANDARD AND NEVER HAS CAUSED PROBLEMS new 45 webber carbs: YOU MAY EVEN WANT TO CONSIDER BIGGER DEPENDING ON HOW MUCH POWER YOU WANT. ROBT AND I HAVE BEEN DISCUSSING 45 VS 48MM ITB'S LATELY AND IIRC, HE SAID 48S ON HIS CAR YIELD ANOTHER 18BHP (!!!) BUT DO LOSE MID-RANGE. THE 45S ON MY CAR ARE NOW HOLDING IT BACK...ALTHOUGH I'M GUESSING YOU WANT TO RE-USE THE 45S YOU HAVE ALREADY? motec ignition management? GET A MOTEC M800 AND SOME THROTTLE BODIES, YOU KNOW YOU WANT TO lightened flywheel: GO 5KG ON THIS AS IT'LL STILL BE NICE COMMUTING ON THE STREET - <4KG IS GETTING A BIT SERIOUS all bottom end balanced as one: IF YOU GET CUSTOM MADE PARTS, TRY TO BUY THEM FROM A RACE/MACHINE SHOP THAT CAN DO ALL THE BITS IN HOUSE - FROM THE FLYWHEEL TO THE RODS AND CRANK will the 83.5mm pistons even be ok in this setup? CAN'T COMMENT ON THIS, AS I'VE NOT DONE IT - LOOKING AT THE BLOCK THOUGH, IT SHOULD BE FINE WITH THIS SIZE RE-BORE anything at all you can add or advise on would be fantastic! the sort of power/rpm ill be looking at? I'M GOING TO GUESS YOU'LL GO SOME CAMS IN THE REGION OF 290-300DEG WITH AROUND 12MM LIFT. PROVIDED EVERYTHING IS BALANCED FOR NO UNEVEN FRICTION AT HI RPM, YOU'RE NOT PINKING, AND THE ENTIRE BOTTOM END IS STEEL, YOU SHOULD BE SAFE TO OVER 9000RPM. I'M NOT SURE ON POWER FIGURES WITH CARBS, BUT I CAN'T HELP THINKING THEY'LL HOLD IT BACK SLIGHTLY, SO I'M GOING TO GUESS ON 180HP AT THE WHEELS WITH A VERY VERY GOOD TUNE. HOPE THIS HELPS AT LEAST A BIT, CHEERS, Stu
de ja vu? m8! thats fackin brilliant ya know,every little bit of info helps,fantastic! i think the oil pump i saw was from autotech,cast iron i think? but its only for solid lifter heads yeah ive spoken about the carbs to a m8 who runs 48's or 50's i forgot... but id like to try them first as they cost a bit to buy,and was thinking i could keep it cheap by just altering the chokes etc... then if they are holding it back id have to sell em thanks v much m8
ahh,nice one... have you any idea on a safe attainable rev limit for the hydraulic head,probably with uprated valves/springs and retainers? how high can yours safely rev,not that theres any point in going past max power/revs... cheers m8. Edited by: riley
Before the cylinder head is flown you really you need to decide the full engine spec. The bore size and cam choice will make a difference to the head as will the carbs almost definatly, someone good like blydenstien, if he knows these modifications, can make slight alterations to tailor the head to the engine. As for the carbs, run em I say. They won't be as civilised as throttle bodies and ecu but they will still work if setup carefully, but also will need a fair amount of tweaking, they can go out of balacnce quicker than you think. 50's will probally be what your after if you want to rev high.. I cant comment specifically to the vw head, but id say it would take 8000rpm occasionaly, maybe a bit higer with uprated bits..IIRC the VW rally cars were limited to this, but that could be to do with the rules..
I would disagree with H8SV8S about flywheel weight. My last flywheel and my current flywheel are both 3.3Kg's and it has no problems staying smooth and tractable. If you get the bottom end knifedged and balanced you should really get all the pistons, rods, crank, pulley, flywheel and pressure plate balanced to each other.
Riley, bear in mind that if 45mm throttle bodies are holding back RobT's ABF then even 50mm carbs are likely to hold yours back. As a general rule of thumb you can't go higher than 90% on choke size so with 50mm carbs () you'd probably have to run 45mm chokes. No chokes in throttle bodies, so you've actually got a full 45mm. For the price of a good set of DCO/SP 48s or 50s you're not far off the price of a throttle body setup anyway. I'd be looking at getting management which can run just the ignition on your carb setup or handle injection if you do need to go to throttle bodies.
Your motor would have a longer torque band though (also a lower one). You'd find that driving the motor daily (if it had big cams) it'd constantly be falling out of the torque band as you decellerate in normal driving. On the track, it doesn't matter so much as it's not as dominated by stop and start driving. You're right to an extent but I know I wouldn't like a <4kg flywheel on my engine (bearing in mind it's a daily driver)
I'm using a sub 4 kg flywheel and knife-edged and lightened/balanced diesel crank( so even lighter than usual). Believe me it's ok for everyday use, and will easily rev past 7000 all day long .
I know 268's ain't massive cams, but it was still ok on them. I would have thought with TB's and a fully mapable system you would have a better spread of torque than me..? Just an opinion.. but i can't see what the problem would be personally.
cheers guys good stuff so far tubs,has such a light flywheel had any major noticeable effect on the torque or up hill pull? madmk4,cheers 4 the info regarding cam spec and bore size,id say im decided on going for 83.5mm bore. ive never had any trouble with the carbs,think its a case of how well theyre set up. greg s,good point! about the ignition/fueling ecu,something to think about... do you know the max choke sizes for 45's? and for what reason would carbs hold the engine back? fueling or air flow? or both? thanks a lot guys im not really looking to build the ultimate performer,just something that will go well with some high revs and oldskool flame spitting,a real weekend toy/road legal track weapon. partly why id like to keep the carbs too,not too fussed about getting the absolute max from everything.
Riley - i can honestly say it pulls better up hill now. I got 5mph more up a very steep local hill after fitting it - the flywheel was the only difference made at that time. I've noticed nothing but benefits from fitting it.
sounds good to me im decided on having one ill just do an "ip,dip dog sh1t" as to which weight ill probably go pretty light i think,cheers... Edited by: riley
I suspect both air and fuelling would get to be a problem when you're aiming for 220bhp+ from 45s. According to the 90% rule, 45s can take a max 40 or possibly 41mm choke. Edited by: greg s
cheers m8 thats something i know will definately need changing then,ill see how the carbs go,and in the meantime i could be looking for some 50's or 'maybe' look into t/bodies,easy enough to change at a later date+r/r time and stuff. few points from dex...
