pies Posted May 27, 2008 Share Posted May 27, 2008 ive been thinking too much and my head hurts.whats the smallest 6 cyl engine you could run 42mm ITB's on and still be able to drive it happily on the street (without loosing all bottom end torque)? would you get away with a 2litre? or would it be safer to run with a 2.5 or even a 3? UJ confused th shit out of me last night 42's would be fine on a 2litre.My brother's Z runs 44's Mikuni's on a 2.4, it's almost perfect, little to no hesitation etc. Correctly jetted etc. Possibly slightly different between carbs and EFi but, wouldn't think dramatically so being you can change injectors to compensate. cos thinking about it. they are designed to run on a 1600 4 cyl. 400cc per cylinder2000cc 6 would = 333.33333333333333333333333333333333333333333333333333333333333cc per cylinder so thats a 66cc difference... not tooooo big a difference is it? It is a fairly big difference but I still think it'll run sweet as. It's not so much the engine size as how much air the thing can flow, to the best of my knowledge.I would say a 1G-FE head (that's what you're using them on eh?) will be flowing much less than a 20V. Then you calculate your intake runners and exhaust manifold appropriately to "tune" the torque characteristics. GENERALLY speaking a longer inlet tract will increase velocity, so you should make some low end torque gains. going onto a 1G-GE head. So if i need to run longer intake runners, will i be ok having the inlet of the throttle body pointing in an upwards direction? or do they need to be horizontal? Beauty of throttle bodies... you can mount them on a incline since there's no floats and junk to worry about like in carbs. But when you look at it, a 1G-GE is about 160hp yeah? A 20V is somewhere in the 130hp range from memory, so I would say they'll be more than adequate. Using educated guesstimations!!! continue... Quote Link to comment Share on other sites More sharing options...
Honda Ass Dragger Posted May 27, 2008 Share Posted May 27, 2008 I hope you have purchased an aftermarket ecu, because if not you are wasting your time, as ITB will not run on any stock toyota ecu's well they will run but like a bag of shit, this topic has been discuss so many times on gd, so you will need a mega squirt or a link so don't waste your time or money get the car going sell it and go hard core on your 2 door. Also no reason you could run itbs and a turbo on your 2 door Quote Link to comment Share on other sites More sharing options...
pies Posted May 27, 2008 Author Share Posted May 27, 2008 even though the 1g-ge is running MAP sensor? Quote Link to comment Share on other sites More sharing options...
Honda Ass Dragger Posted May 27, 2008 Share Posted May 27, 2008 problem is the fuel curve on speed density is way different for itbs then single manifold. In that fuel on itb motor at say 75kpa is next to nothing (say 5-10%), but on a single throttle motor it could be 40% load... so you can get an itb motor running on stock ecu to fuel ok at idle and then again near full throttle... but in between its going to overfuel. also accel enrichments (that good sound you get when you just stab the gas) will be crap on std ecu. been there, wouldnt waste me time again. power up on itbs is not much, so need to make sure fuelling is bang on to make the most of it (response, noise). As quoted from Toyota Yoda Karl Skews Quote Link to comment Share on other sites More sharing options...
mikuni Posted May 27, 2008 Share Posted May 27, 2008 ITB's. My favourite topic Continued from schpam.. blacktop throttle bodies are wwaaaaayyyy to big for a 1600. Apparently the TRD ones you buy for a 3sge BEAMS are identical so obviously they got a bit carried away when designing the blacktop (as we all know they did with the 16v ports) so I guess being a little large can't hurt too much.. thats what she said. Also, after seeing 1G-GE ports they are fucking HUGE! Spence was telling me about a dude on toymods that has one making good horsepower (fully built turbo) and was saying about how well those heads flow while standard. I imagine that with no port work and altered cam profiles you would get good gains from an ITB setup. While running a squirt ofcourse and for this very reason its probably not worth mucking around with for a daily. Just too much mucking around with to get right IMO. Quote Link to comment Share on other sites More sharing options...
pies Posted May 27, 2008 Author Share Posted May 27, 2008 yea. the plan was to run 1gge on standard MAP computer, but after a little re-search i dont see this as being a good idea. Quote Link to comment Share on other sites More sharing options...
Unclejake Posted May 27, 2008 Share Posted May 27, 2008 Looks like the answer is don't fuck with it unless you have an aftermarket programable computer thing and lots of time. If it was me I would bolt three DCOE Webers on there and find a way to get some pushrods installed. Then I would start drilling holes somewhere. Amen. Quote Link to comment Share on other sites More sharing options...
pies Posted May 27, 2008 Author Share Posted May 27, 2008 Looks like the answer is don't fuck with it unless you have an aftermarket programable computer thing and lots of time.If it was me I would bolt three DCOE Webers on there and find a way to get some pushrods installed. Then I would start drilling holes somewhere. Amen. rofl... i dont have a drill Quote Link to comment Share on other sites More sharing options...
Spencer Posted May 27, 2008 Share Posted May 27, 2008 mean about time there was a decent thread in tech not much to add that hasn't been said, Silvertop quads are fine on a unworked 2jz so would be ample for a 1gge. As said above your screwed unless you want to dive in to a squirt or buy a link dabbled with stock ecu's before as stop gap on a mates car and only place it runs fine is idle and full throttle with a map ecu. Afm works better obviously but then you need a plenum and loose probably the only gain your after which is the noise . as brad said about 1gges the ports are massive the guy on toymods who runs a 9 on one says for boosting RB's etc dont even come close to making the same power at the same boost levels as the head is so unrestrictive. Way to big for N/A use but would be awesome with cams and ITB's in a light car Quote Link to comment Share on other sites More sharing options...
Maru-So Posted May 27, 2008 Share Posted May 27, 2008 Im planning to build a 1gge on R1 or similar bike carbs. Ive been researching the topic for a while now. R1 carbs come in 38mm 40mm and rare 42mm. Seems to be lots people running 38mm tb and carbs on 2L. Quote Link to comment Share on other sites More sharing options...
kpr Posted May 27, 2008 Share Posted May 27, 2008 one thing that may not be so good, with the massive ports and silvertop throttles. is the low velocity area it'l leave at the port. my understanding of the best setup is, to slowly taper the inlet runner down from the bellmouth, to the port. witch will give you hi velocity at the port/ valves, increasing cylinder fill. going too big on the throttle size shouldn't matter too much. but throttle size silghtly bigger than the ports would be best option as you can mount them close to ports to increase throttle response while keeping a good taper. going bigger would mean moving them further from ports. loose a little throttle response and driveablity (depending on throttle linkage setup) but should not effect power at all, if taper and runner lenghths are same. running something big enough for the likes of a 1g or big port 4ag ports, maybe getting a little silly tho and yeh will suck on stock ecu as others said. tune with tps vs rpm is all good. long as you have plenty of rows in fuel map at light throttle Quote Link to comment Share on other sites More sharing options...
mikuni Posted May 27, 2008 Share Posted May 27, 2008 mines only on tps vs rpm and its all good. need map for better throttle enrichment though because it hesitates mean when you just stab the throttle. and yeah, taper throttle has been proven to be a big advantage on a lot of XE (BTCC etc) engines that I've read up on. Quote Link to comment Share on other sites More sharing options...
lowlancer Posted May 27, 2008 Share Posted May 27, 2008 Hey Mikuni, could you chuck up some links to those BTCC engines builds etc that you mentioned? Could be interesting. Quote Link to comment Share on other sites More sharing options...
mikuni Posted May 27, 2008 Share Posted May 27, 2008 Sorry boe,don't have anything saved and I read up all that stuff years ago. Just search google for ex-btcc race builds. Heaps of cunts have bought all the old btcc cars and engines so theres lots of info around but its difficult to find. As for xe stz the best sites I could find for parts and info are QED: http://www.qednet.demon.co.uk and and SBD: http://www.sbdev.co.uk If you find any dedicated BTCC stuff post them up. We need more lush race engine threads I'm sure peoples will be interested.. Quote Link to comment Share on other sites More sharing options...
kpr Posted May 27, 2008 Share Posted May 27, 2008 what ecu are you running? i just wound heaps of throttle enrich into mine. fixed the problem. Quote Link to comment Share on other sites More sharing options...
mikuni Posted May 27, 2008 Share Posted May 27, 2008 Will have to try that when we get it on the dyno. Running lem g3 ps, keen for grudge match at meremere when I get my car running again I'm hoping for about what you were running. Quote Link to comment Share on other sites More sharing options...
Testament Posted May 27, 2008 Share Posted May 27, 2008 Looks like the answer is don't fuck with it unless you have an aftermarket programable computer thing and lots of time.If it was me I would bolt three DCOE Webers on there and find a way to get some pushrods installed. Then I would start drilling holes somewhere. Amen. X2 triple 40DCOE with 32 chokes would be tumeke Quote Link to comment Share on other sites More sharing options...
Spencer Posted May 27, 2008 Share Posted May 27, 2008 Im pretty sure 99% of your problems brad would be sorted with some more time spent of the tune rather than using map need to get a laptop and play with some shit your self maybe especially with this weather get that cold start shit sorted As you stated kpr pretty ridiculous trying to make a taper manifold on a big port but the silvertop throttles are a similar surface area so at least you wouldn't have a enlarging manifold. The other thing with going ITB's or bike carbs on a 1gge is your going to loose tvis and have a massive hole in your torque curve the itbs may gain power from removing the restriction of the factory setup but you will end up with an over all slower car (especially in the whales it comes in) unless you cammed it with suiting mods. Unless going all out I'd only go itb's on a 1gge for sound Quote Link to comment Share on other sites More sharing options...
kpr Posted May 27, 2008 Share Posted May 27, 2008 i had mine setup with the 4d mapping on the link to start with. map with tps overlay. worked ok. but switched back to tps only in the end. my map signal was a bit shit and doing strange things to the afr. ive almost got the numbers maxed out in parts of the accel clamp table. just keep winding it up till it feels good. keen for grudge Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.