stephenw22 Posted October 1, 2003 Share Posted October 1, 2003 Where does the heat riser pipe go to? Mine just dangles down to near where the catalytic converter is. It seems like my carb is freezing up in the morning, and that heat riser looks like it wouldn't work very well. What are the common upgrades that people here have done to carb'ed engines? Quote Link to comment Share on other sites More sharing options...
Snowman Posted October 1, 2003 Share Posted October 1, 2003 There should be a little pipe leading from the heat shield on the first cat that the heat riser hooks onto. As for modifications, there isn't too much you can do to the hitachi carb itself, other then junking it and getting a weber. I have experimented with putting additional vacuum on the secondary to open it faster, but never really perfected the system. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 1, 2003 Share Posted October 1, 2003 You can wire the secondary to open mechanically with the primary. And I think they are somewhat jettable - if you can find jets that will work with them. Could be done, but the weber is better since they aren't quite so quirky, and there's a huge aftermarket following of them. If you start modifying the hitachi, your on your own, and you'll never get the performance of a weber anyway - the hitachi is just too small. GD Quote Link to comment Share on other sites More sharing options...
stephenw22 Posted October 1, 2003 Author Share Posted October 1, 2003 Is the carb intake the same as the spfi intake? Could I pop off the carb and slap on an spfi throttle body? Just imagining a little megasquirt action here, down the road. Carbs are nice, but I like how much nore precisely I can control the engine with EFI. Plus, it would give me a little experience with the megasquirt unit before I start any more 'exotic' projects. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 1, 2003 Share Posted October 1, 2003 Megasquirt is certainly possible, but the original SPFI would probably not be a good choice. The carbed engines are different - the intake manifold is different, as is the compression ratio, and cam profiles. While it may work, it wouldn't be quite right is my guess, and you wouldn't get as much power. The SPFI engines have a higher compression ratio. You would also need the complete wiring harness, and the ECU - also the SPFI distributor is different - it incorparates a crank angle sensor. This can and has been done to EA81's (I realize yours is an EA82), so it would work, but it's probably more work than you think. I've been contemplating doing this to my Brat, so if you do it, tell us how it goes. Take lots of pictures, and make nice wiring diagrams too. We will all learn from your experience. GD Quote Link to comment Share on other sites More sharing options...
MilesFox Posted October 1, 2003 Share Posted October 1, 2003 if you wanted to go the spfi route, just swap on the entire spfi manifold Quote Link to comment Share on other sites More sharing options...
stephenw22 Posted October 2, 2003 Author Share Posted October 2, 2003 If the manifolds are different, then a swap would be the best choice for me. The main reason I'd be doing an spfi swap would be to learn more about working with the megasquirt computer. I figure that the spfi setup would run a little more smoothly than an mpfi setup. Anyways, back to carbs for a sec, and the heat riser. My cat has no such pipe for a heat riser. Does the heat riser tin just snap onto the cat, or am I looking at a car that has had the exhaust replaced at some point? Would I be able to rip the tin heat riser off a junkyard car's cat, and spot weld it to my cat? Quote Link to comment Share on other sites More sharing options...
archemitis Posted October 2, 2003 Share Posted October 2, 2003 yah, its just a little 1.5 inch pipe coming off the top of the heat shield on the cat, on my carb wagon. whats with the gay guy dressed as spiderman? Quote Link to comment Share on other sites More sharing options...
stephenw22 Posted October 2, 2003 Author Share Posted October 2, 2003 The dancing Spider-Man is just an animated gif I saw one day on the web. I thought it was pretty funny, so I've kept it now for a while on my computer, and figured I might as well use it if I've got it. I'll have to keep my eyes open for a wreck with a heat riser, then. Hopefully, one of the yards in town will get a carb'ed Subaru in by the end of the month (after about Nov 1 here, the snow won't melt away anymore, so it's officially "winter"). Quote Link to comment Share on other sites More sharing options...
archemitis Posted October 2, 2003 Share Posted October 2, 2003 you could have a shop or something weld a pipe onto your exhaust somewhere, with a couple of tac welds. it would work too. 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.