500 efi upgrades
 

I'm running twin 500 efi's with 215 reliable hours. Looking for more hp without supercharging... don't want to compromise reliability.

Thanks for any suggestions.

Aluminum heads at least, cam, computer remap by some experienced. Thats what I would do if I didn't supercharge mine.

Any idea on hp gains to be had from this?

A good 25 to 50 hp I have read here, depending on the cam.

You can buy the heads with new valves and springs already installed. Your close to the hours of replacing the springs anyways.

Try a search and you'll find alot on this engine.

How about making them 540's.

Tyler did mine this winter. Replaced heads with Darts, his cam design, MSD ignition, redid my carbs (he prefers EFIs) and I dynoed at 585 per side. Carder

Thanks - gives me some direction... now I have to find the right shop to handle the job.

Use a shop who has doen the work before. Ask the shop for referenses, and call the customers to see how it went. For a job like that, I would insist on a dyno tuned finished product.

Totally agree with Jeff...you can't tell how youv'e changed the dynamics of the engine without the dyno sorting it all out. Carder

I also have 200 hours on our 2000 Slingshot with 500EFI's. E-mailed Crockett and talked to Joe @ Hustler this week, still waiting for a reply from Tyler but have heard of good things from his shop. I would like to see the motors in the 600-700 horsepower range. Are there any advantages to N/A vs. supercharged, i would also like to see engine life of 300-500 hour range.
Thanks Steve

Post anything that you hear, if I don't sell mine, would be very interested in hearing about what options are out there for EFI upgrades without going to supercharges.

Tyler's got 496/502 EFI package up-grades on his website... you can use that as a base line, and get a base line cost idea, too. 500 EFI's will probably increase in performance proportionately. Carder

Any thoughts on increasing to 540 ci., porting stock heads, cam change, and ECU reprogram vs. 500 ci., ported aftermarket heads, cam change, and ECU reprogram?
Thanks Steve

call Richie Zul. Zul Racing engines. he has done wonder's with the hp 500 and hp 525's.

Good option to get over 600 hp. But its all how much $$ you want to spend. I Whippled mine and have more than enough hp . But wasn't cheap.

Originally Posted by NEVERSATISFIED
Any thoughts on increasing to 540 ci., porting stock heads, cam change, and ECU reprogram vs. 500 ci., ported aftermarket heads, cam change, and ECU reprogram?
Thanks Steve


Any more thoughts on the 500 EFI with aftermarket heads VS. 540 with stock ported heads?

The most Ive heard of is 648hp out of a 500efi from Mark at Precision Marne in La and Riche Zul.Thats with all the tricks etc $$$

Mark built another 500efi with just dart iron eagle heads,cam,port work to the intake,throttle body,It made 598hp.

Tyler should also have a similar package


If your paying someone to do all the work you might come close to what a supercharger would cost,With 200 hours you could get away with headgaskets,maybe valveprings,On a Whipple at 4-5lbs of boost should put it in the low 700hp.Being easy with it the XR's should live.


myvalium at 750hp in your boat should put you at 96-98easy