Stephan's SLC Build Log

Stephan E.

Supporter
Hello Johan,

That is exactly the question which drove every ITB user into insanity. There is no free lunch using this setup. It is race breed and requires rpm to properly function since there is not enough vacuum until about 5000 rpm for a MAP and the TPS only was always assuming a constant airflow at a certain throttle position but did newer knew the actual load. A real issue in the past but modern ECUs such as yours allowing Alpha-N and Speed density to be combined and to kick in at certain trigger points. Also atmospheric pressure and temperature are now measured and included. The Holley Dominator is actually a good match in addition to the MegaSquirt. Both have short and long term self tuning capabilities and dedicated ITB functionality. Nothing for a parade or 1700rpm in sixth gear on the highway. You trade lightspeed throttle response, power increase, sound and looks for driving comfort. My Audi V8 gear ratio will go very well with it.

Stephan
 
Last edited:

Johan

GT40s Supporter
I see, haven’t really checked everything the Dominator can do, it’s a superb ECU, maybe a little overkill for my lightly hotted LS3.
The HP would have been sufficient.
Got hold of the TT vents on ebay.de, thanks.

Johan
 
Welcome to the ITB club.

Happiest day of my life was when I bought ITBs for my 917 and was like 'FVCK YEA!' when I unboxed them and put them on the car

Next happiest day of my life was when I threw those motherfvckers into the garabge - after 4 days on the dyno and nothing but issues I said 'FVCK THESE STUPID PIECES OF SHIT'

Sure, they work great if you're tracking the car, but on a street driven car nothing but god damn problems. No, I do not want my headers glowing cherry red after idling for 10 seconds and having 0* of timing.

Did I mention I hate ITBs and the misery they put me through :)
 

Stephan E.

Supporter
Welcome to the ITB club.

Happiest day of my life was when I bought ITBs for my 917 and was like 'FVCK YEA!' when I unboxed them and put them on the car

Next happiest day of my life was when I threw those motherfvckers into the garabge - after 4 days on the dyno and nothing but issues I said 'FVCK THESE STUPID PIECES OF SHIT'

Sure, they work great if you're tracking the car, but on a street driven car nothing but god damn problems. No, I do not want my headers glowing cherry red after idling for 10 seconds and having 0* of timing.

Did I mention I hate ITBs and the misery they put me through :)
Hi Alex,

I remember you are telling me this before. I had ITBs and weber carburated open throttle cars in the past and I am fully aware of what it takes to get them to work. For me there is no better natural aspirated power adder to a race engine, looks and sound like an ITB setup. Not plug and play, nothing for the faint hearted, will take some effort and money for sure but it will be different from anything out there. That is why I chose an SLC to begin with, I just added another chapter to the journey. I am not afraid, compared of what am I going through with my 63 Fuel Injected Corvette this will be a walk in the park. I have done my homework and spoken to reputable and experienced tuners and ITB manufacturers in the country and across the pond before I even got started taking the Mercury induction off the motor. I am lucky enough that one tuner is only 10 miles away. Modern superfast engine management with sophisticated ITB fuel strategies, top end hardware and professional installation will help to get it done or I wouldn't even consider spending this amount of money. I am being confident this is going to work and when it does OMG.

It can be done. LSX putting out 750 HP. Working just fine.
 
Last edited:
I don't doubt it can work for certain applications, but it isn't about throwing money at it - I spent ~$10k on it before I gave up - or skill - I went through 3 tuners - it's about compromises.

Each tuner ended up at the same point - having to pull all timing from the car just to get it to run properly at low RPM. We looked at the Harrop files they sent me about how they tune them and same thing - no timing. I talked with other Harrop owners and they had the same conclusions at me. One guy was like 'OMG I LOVE THEM THEY WORK AWESOME (but I burned the valves and had to do heads-off work, but hey, that's okay because I'm a master mechanic')

As race car at 5000 RPM, sure, great concept. As street car that you want to set-and-forget, not on my life again.
 

Stephan E.

Supporter
Hi Alex,

I understand your frustration. Many factors are playing in such setup. From cam profile, exhaust flow over total runner length etc. If the harmony is not there between all pieces the outcome can be such as yours.
 

Stephan E.

Supporter
Very cool seeing it come to life like that.
Hi Joel,

Still a long way to go. Currently I am working on a completely new wiring harness which turns out to be quite nice when done. ECU choice is imminent. The bad news is my exhaust system is too small for the new output. Too much back pressure. I had to stop kidding myself that the LS stock headers will do the job. Need new headers and piping to increase to 3.5". The new BTU calculations are telling me that is time to retire the SLC stock radiator which requires a new front end design to install a larger unit. I am thinking of a new space frame front end incl. hinges with quick release to take the whole thing off in a minute. Slowing down due to home remodeling...
 
Last edited:

Stephan E.

Supporter
Wow! Now that is impressive Stephan.
Hi Joel,

Thank you for the compliment. It took some imagination but it will eliminate the need for a sound system. A full orchestra in the rear compartment. It certainly was a challenge but that is what a SLC is all about. Still, a few bridges to cross...
 
Last edited:

Stephan E.

Supporter
Voll geil!
Danke Markus,

Immer wieder mal schoen ein paar nette deutsche Worte zu lesen. Freud mich das mein kleines Projekt in Deutschland Freunde hat.

Gruss,

Stephan
----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Thank you Markus,

Always nice to read some german words. I am glad to see that my little project is having friends in Germany.

Cheers,

Stephan
 
Last edited:
Top