mitch_mac Posted October 13, 2009 Report Posted October 13, 2009 hey guys just picked up some DHLA 40 dellortos i have just ordered a manifold and low profile k&n filters for it and made up the throttle cable mounts ect ect just have some fitting questions will i need a bigger fuel pump? (from what i hear the only need about 4 psi and a standard pump is 3.5-4psi?) the carbys were on a 2ltr alfa engine when i got them will i need them to be rejetted to suit 4k? anything else i may need to know? thank guys :) mitch Quote
mitch_mac Posted October 13, 2009 Author Report Posted October 13, 2009 oh and if anyone in brissy can come help me once they are on to tune and get it running and knows what they are doing I'm happy to pay or shout you a carton or something ive never played with carbys befor and id rather not stuff it and wouldnt mind some pointers thanks mitch Quote
Taz_Rx Posted October 13, 2009 Report Posted October 13, 2009 Stock mechanical pumps will do in the meantime. Plan to upgrade to an electric pump and adjustable regulator though. Yes you'll need some down jetting. A couple of hundred $ would be very well spent on some dyno tuning to get it spot on. :) Quote
mitch_mac Posted October 13, 2009 Author Report Posted October 13, 2009 how many hudred we talking here haha i knew it wouldnt be cheap but can anyone give me a ruff idea of how much getting theres done cost? would i be able to get it running as is to drive it to get jetted just have it running rich? better than leaning out right? thanks mitch Quote
leigh Posted October 13, 2009 Report Posted October 13, 2009 I have twin 40mm webers on my 5k! they were originally off a 1800 alfa.... I was able to get them to run not very driveable tho! :) I got them re-jetted and tuned on the dyno and set me back about $500 best thing ever! But i had to take it to and old bloke at workshop first to get him to balance and set the floats! As the dyno owner wouldn't do that for me! :y: Quote
philbey Posted October 13, 2009 Report Posted October 13, 2009 I'm running the same setup on a 5K. - You will be fine with the stock fuel pump, it provides ample flow and pressure on mine. You will definitely need to install a fuel pressure regulator as the stock pump will provide more than 3-4 PSI, my Holley Red is working fine. - Buy a book on Dellortos. There's 2 good ones on the market, I forget their names. I have one it's very handy but it focuses more on the Downdraft DRLA's, but it's still very relevant to DHLAs. - +1 for a definite rejet. What I would suggest is get the pen and paper out and some screw drivers. Pull out your emulsion tubes and jets (brass screw in units under the plastic cover) and note down any numbers you see on them. Peer down the throats and note the number cast into the Chokes (will be something like 28/30/32/34/36). The book you buy should be able to explain what these numbers mean and how to size the jets correctly. Even if you don't do it yourself, I recommend it so that you understand better what and how they work - If you're confident with that, you could collect the jets and chokes you need for your spec yourself and swap them over. YOU WILL STILL NEED DYNO TIME. - Read up on Balancing the carbs, even if you do it crudely using the linkage adjuster it will be beneficial. - The car should be fine to drive to the dyno tuner. Even if it's a little lean, casual, daily driving shouldn't cause any real concerns, it'll most likely just run like shit and be 30% down on potential power. - You will need dyno time. Definitely. One afternoon of dyno tuning set me back 290 bucks. I went in with a car that was reasonably driveable but with a couple of flat spots. When it came out I'd gone from 45 to 68kw, it idled better, no flat spots and the risk of top end lean out was no longer. Find a Dyno tuner that has plenty of alfa experience and they'll probably have a cache of jets and emulsion tubes for you. Enjoy. Quote
philbey Posted October 13, 2009 Report Posted October 13, 2009 Just read leigh's post. Buy a manual and set the floats yourself. Balancing should be fine tuned if necessary by the dyno tuner. Some earlier DHLA's have a port for connecting a balancing gauge and you can actually tune the balance on each individual throat! I have later model DHLA-G's and I don't have that bleed screw, so it's basically just up to the linkage balance between the 2 carbies. Quote
mitch_mac Posted October 13, 2009 Author Report Posted October 13, 2009 thank guys once again more than helpful =] i have a fuel presure reg here to so ill slip that in yeh aslong as it gets me there ill just nerse it there id say itll chew the fuel the whole way but id rather do as much as i can myself to save me some moneys and a dyno tune will be on the cards for sure anyone in brissy no of a good dyno place that are good with carbys I'm thinking carbtech in redcliffe but i don't no if they dyno tune Quote
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