coln72 Posted February 25, 2009 Report Posted February 25, 2009 Factory downdrafts are hard to find and can be expensive to setup. never had that issue. Both of the sets I've had cost nothing but time to set up. Quote
Redwarf Posted February 25, 2009 Report Posted February 25, 2009 I think I can actually answer this one with a bit of authority, as I've had twin everythings over the years. Factory aisans: Would do the job. Basically bolt on ten Hp. The set I had went straight on the car and worked like a charm. Had them rebuilt once, and they behaved exactly the same. Set and forget, but getting really hard to find. I think Cameron has my set these days, after going through the hands of a number of Rollaclubbers. SU: I had a pair of HS4 (1.5") SU's on a hot (and I don't use that term lightly) 1360cc 3K. They were just enough for that engine, they would really suit a mild 4K. I had them professionally rebuilt, followed by half a day on the dyno. Never touched for about 2.5 years after that, and I was really impressed by them. Hard to find maniflods to suit, although a few have appeared in here recently. 1.75"' Su's would be too big on a 4K. Weber/ Dellorto: Notice I didn't say Solex. Webers (and Ill use this to cover Dellortos as well) are the grand-daddy of them all. I picked up alot of torque and hp, and started using epic amounts of fuel. Induction noise to die for. Looking at the thick end of $1000 to set-up. If you think you can get away with out dyno time, you're kidding yourself. I love Webers, but they can be summed up with: Big grunt, big dollars, big noise, big fuel bill. Quote
philbey Posted February 25, 2009 Report Posted February 25, 2009 oh ok never have come across a forum who cares for spelling and punctuation, sorry for the trouble ill make more of an effort from now on... Read the rules. Also, you'll notice that this forum doesn't have the typical amount of cockheads and retards that most others do. never had that issue. Both of the sets I've had cost nothing but time to set up. Sorry, I punched that response in quick without reading. They are hard to find and expensive to buy (400+) and getting rebuild kits etc seems to involve mixing and matching bits from multiple kits. Quote
coln72 Posted February 25, 2009 Report Posted February 25, 2009 Sorry, I punched that response in quick without reading. They are hard to find and expensive to buy (400+) and getting rebuild kits etc seems to involve mixing and matching bits from multiple kits. I must of been lucky. 1st set cost $25 complete and the second set started with a free manifold. :lolcry: I never ran the 3kb carbies but two single carbies, if you get my meaning and finding bits for them was searching through my big box of carbies until I found what I wanted. Listen to Red as if he hasn't tried it is probably not worth trying. Quote
philbey Posted February 25, 2009 Report Posted February 25, 2009 I've kept my eye out for them for about 2 years, you definitely got a good deal! Quote
DDeano Posted February 25, 2009 Author Report Posted February 25, 2009 webers seem to be the way to go, i don't mind a bit of added fuel consumption but how bad are we talking??? double the fuel usage then standard? not quite that much? give me a rough idea how many k's to a tank??... i also own a mazda rx7 series 4 so I'm kinda used to having poor fuel economy... Quote
camerondownunder88 Posted February 25, 2009 Report Posted February 25, 2009 Hi, Factory twin carbies are nice but as stated HARD to get these days. Yes I own Robs old set tilll going strong but ATM they do need a tune. I rebuilt 2 sets of these now and finding parts HARD. The needle and seat replacment for them now listed is the SAME as the single carbie and the needle and seat in the twin carbies is smaller. Also jets are smaller and the kit I got had larger jets in it so if you get a set can be hard to rebuild but CAN be done again mix match parts and recon old parts. They actually sound really nice to. Also if you are hunting a set of original twin carbies you come across them for $25 to $500 pending condition. I Have paid a lot for them and a lot of them have the water cooling pipes cut off the manifold as it used to foul on extractors. Also I own a few sets of these BUT I only have ever got my hands on 1 yes 1 original exhaust manifold for them there different to normal exhaust manifolds so if you get a set of factory twins best to run extractors as a normal exhaust manifold wont match up. Cheers Cameron Quote
snot35 Posted February 25, 2009 Report Posted February 25, 2009 I guess the pertinent question is, what do you hope to achieve from changing to new carbs? What do you want the car for? And no, it's highly likely it won't be as thirsty as your RX7! :lolcry: Quote
DDeano Posted February 26, 2009 Author Report Posted February 26, 2009 I guess the pertinent question is, what do you hope to achieve from changing to new carbs? What do you want the car for? And no, it's highly likely it won't be as thirsty as your RX7! :lolcry: i hope to achieve some more performance out of the car before i decide to do an engine conversion and at the same time make it sound tuffer and I'm doing it cause i plan to start entering the car in some events like hill climbs, sprints etc not to seriously just for a bit of fun, hope that answers your question... Quote
coln72 Posted February 26, 2009 Report Posted February 26, 2009 If that is the case, you will get a lot more gain in getting the cam reground and the head shaved/port matched than from the twins. Should be able to do this for less than the cost of setting up twin Webers. Quote
DDeano Posted February 26, 2009 Author Report Posted February 26, 2009 ill do both, I'm happy to spend abit of dosh on the rolla... Quote
leigh Posted February 26, 2009 Report Posted February 26, 2009 I'm in the process of building up a 5k for my car with twin webers, Fully balanced bottom end, aftermarket pistons, mild cam, ported and polished head and matched to the extractors and inlet manifold and double valve springs! So hopefully should go along well! Just trying to work out the jet and choke sizes now! But yeah the cost soon does add up quickly hahaha Quote
snot35 Posted February 26, 2009 Report Posted February 26, 2009 For the money you're thinking about spending on machining, cams and twins, I'd probably just say bugger it and do the conversion! At the end of the day you modifying an old motor that is quite small in capacity. If you can do some of the work yourself you'll be better off with something that has cams in the right spot, more of them, more valves and probably EFI. Of course this all depends on state laws on modifications, but you did mention you were going to do a conversion eventually anyway. Make sure you check the regs of the classes you plan to race in though. If it's just for a bit of fun then it doesn't matter. If you actually want to be competitive then you have to give it more thought. Quote
coln72 Posted March 1, 2009 Report Posted March 1, 2009 But I was never beaten by a 4age whan I was competing. This was in my 5k'd KE20. Just cause it may be old and small doesn't mean they need to be slow. Quote
!!!! holden2100!!!! Posted April 6, 2009 Report Posted April 6, 2009 hey guys just bump in here for a question have any of use heard or thought about putting gsx1100 carbies on a 4k???? (mite have to get them tuned proply tho) and does any one now what the best cam profile is for a 4k with 60thou oversized pistons and head shaved 40thou /ported and polished I'm very new when it comes to cams? plz help Quote
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.