Building a 200HP Twin Spark

[69alfa]

Hard to tell without driving it on the road but I will let you know .

[GTV4EVR]

Quote:

Originally Posted by 69alfa IT"S ALIVE !!! All seems well . No leaks or bad sounds and no smoke I drove it out of the garage to turn it around and I stalled it The new clutch may take some getting use to . It is idling ok but not as well as it did before. I think the Inovate O2 controller has lot it's programming . Not sure how it happens but it did the same thing last year. The computer can run fine without the O2 sensor but it works much better with the correction data from the sensor. Should get it all sorted after work tomorrow and do some test driving on Saturday . Then off to Mosport on Sunday to watch the races and do a lap at the lunch break

[Nicola]

Quote:

Originally Posted by 69alfa Hard to tell without driving it on the road but I will let you know .

[69alfa]

I will be at the convention but not the tour .
Anyone want to drag race for pinks this year?

[FMG_V6_btb]

Have you tried to install the injectors on the throttle bodies? perhaps you could get some more HP at high speed due to the longer distance, more time for fuel vaporisation...

[69alfa]

I have thought of running two sets of injectors . The inner Alfa ones for low speed and the outer GSXR ones for high speed . I have used one of the throttle body injector ports for a vacuum source . That would have to change but it would be easy to put back . The best thing is the DTA computer supports dual injectors .

The down side would be the dyno time to get it working just right . And the plumbing to get fuel to the two rails . Maybe this winter if I get bored

I just put bigger injectors in this week . They are 399 cc/min the old ones were 190cc/min . All I had to do was remove 45% of the fuel from the map and it starts and runs fine .

I have an dyno run setup for Monday to get it tuned up nice and see how much power she is making . Then off to the convention the next day .

[Seabird]

I am starting to itch all over With my final assembly around the corner seeing yours go together I am having a hard time restraining myself.

Can't wait to see the numbers! Congrats!

Miguel

[69alfa]

I am happy to report the numbers from my first Dyno run on the newly rebuilt motor.

It showed 171.6 HP (rear wheel) at 6500 rpm at that point it hit the rev limiter .

The HP was still climbing well at that point but the motor only had a few miles on it and we left for the convention right after so it was decided not to push it too far.

It is hard to say what the conversion to flywheel HP is . The best info I could find was from Puma Race Engines Technical Guide - Measuring Engine power - engine dynos and rolling road dynos The math would work out to 171.6/0.88 +10 or 205 HP That would be good very good .

It ran very well on the way down to the convention . Needs a few tweeks and a bit of getting use to .

It sure get my heart pumping when the pedal meets the metal

It will ping if it is pushed too hard in too high a gear but it is easy to avoid .
I will refine the mapping to get rid of that when I get back home .

[FMG_V6_btb]

Congratulations!!! seems your have met your power target at the beginning of the project, it's a great power for a spider, how it feels?

[GTV4EVR]

Well done Dave!!!!

[Biba69]

David, make me one just like it. That must feel terrific being rewarded by an extra special TS after all of that time/energy, along with what I'd imagine more than a few (Canadian) dollars later.

[pancho]

Thanks for this whole write up Dave, totally awesome. I've hinged my engine build on this thread - very similar hardware (minus injection) so it should be a repeatable result.

How have you found the cams ? Where is the power range and how do they idle ?

[davbert]

awesome! so much for the people that say the twin spark isnt a worth while swap

[69alfa]

Thanks Guys ! It is a great motor made even better with the right parts.

It does make a few pops here and there but that is just too much fuel on over run .

The motor idles just as well as it did on the old cams . BUT the idle is tightly controlled by the O2 sensor and timing control . A motor on carbs and distributor may not do as well ???

As the engine speed drops from 1200rpm the computer gives it more and more spark advance to keep it running . And the Innovate O2 controller holds the fuel at precisely what I set it to.

[clemensh83]

Hi Dave!

Great to hear that you hit the 200 HP!!! Congrats!

Would be nice to see a dyno graph!

Grats Clemens