I've almost finished tuning my engine with MS. It's one of Jake's 2270 kits and it has a fairly aggressive cam with lift just shy of .500" on the exhaust and intake with plenty of duration and overlap. The valves are 44 X 36 and there is some slight porting. At any rate it will pump a great deal more air than a stock engine.

The only mods I have made to my intake system are rebore of the throttle body to 50mm from the stock 45mm and a K&N air filter in the stock air box.

There has always been a question about the limits of the stock intake system on a modified engine. I think I can say I'm convinced that it will support my engine without trouble with the rebored throttle body.

The proof is in the logs I have been recording and which can be seen on the graph below. This represents acceleration through the first 3 gears with 3rd at WOT. The boxes at the lower left show RPM's at 6400, the manifold pressure is 94 kpa and the throttle position is 100% (WOT).

Atmospheric pressure that day was 97 kpa so the engine drops 3 kpa through the air filter. The purple line in the yellow circle tells the story. It stays at a consistent 94 kpa from the time I open the throttle after shifting into 3rd at ~ 4000 RPM until I shift into 4th at 6400 RPM. If the intake could not supply enough air that purple line would fall indicating the engine is trying to suck more air.

For anyone considering fuel injecting a larger than stock engine don't rule out the stock intake until you prove it will not work. Boring the throttle body is an easy thing for a machinist (cheap too) to do. The hardest part of the whole thing is making a new throttle plate to fit the bigger bore and that didn't take more than an afternoon.

Here's a little closer look at the proof

Dave

Cool work. You can go bigger on the throttle body if you completely rework the top of the plenum. I have a 2270 with stock valves, runners and plenum modified to fit a Volvo 55mm throttle body and it works amazingly well. The cam is a web cam mild injection grind. The vovlvo tb had to be reworked to turn the other way and vacuum lines added, but totally doable. Early mpc and injectors, with 270 ohms resistence b4 head sensor gives me just the right mixture across rpm band !!

Wow Dave tha's really cool.
I am so glad you finally got that motor running as you wanted it.

Perfection is quite hard to attain huh? But it looks like you did it.

QUOTE (Krieger914 @ Feb 8 2006, 11:46 AM)

Cool work. You can go bigger on the throttle body if you completely rework the top of the plenum. I have a 2270 with stock valves, runners and plenum modified to fit a Volvo 55mm throttle body and it works amazingly well. The cam is a web cam mild injection grind. The vovlvo tb had to be reworked to turn the other way and vacuum lines added, but totally doable. Early mpc and injectors, with 270 ohms resistence b4 head sensor gives me just the right mixture across rpm band !!

Tell me about the Volvo throttle body,what car did it come off of,year and some details about the retro fit?

QUOTE (72914S @ Feb 8 2006, 10:04 AM)

QUOTE (Krieger914 @ Feb 8 2006, 11:46 AM) Cool work.  You can go bigger on the throttle body if you completely rework the top of the plenum.  I have a 2270 with stock valves, runners  and plenum modified to fit a Volvo 55mm throttle body and it works amazingly well.  The cam is a web cam mild injection grind.  The vovlvo tb had to be reworked to turn the other way and vacuum lines added, but totally doable.  Early mpc and injectors, with 270 ohms resistence b4 head sensor gives me just the right mixture across rpm band  !! Tell me about the Volvo throttle body,what car did it come off of,year and some details about the retro fit?

Barry get back to work so you can go racing this weekend

I am soooooo ready.

I am working,this is running in the back ground.IS it Saturday yet??? Saturday Sunday

ah dave...you did mod the long tapering intake tube on the air filter box.

k

Dave, was the snout on the airbox modified?

yes. he did change it.

k

Is it proven that the stock throttle body is a restriction on these big bore type IV engines?

Sorry to take so long to respond. I've been traveling for work and had no communication. The throttle body is from a mid 80's 2.3 L four. I don't rem the model but there are tons out there. The plenum mod I first made to see if this would even work was an adapter plate made out of a 1/2" chunk of aluminum. The butterfly plate on the vovlo tb is 55 mm. the tb flare to about 58. The stock plenums opening is maybe 50mm. I got an extra plenum and cut the stock mounting plate off and had a machinist make a custom plate that welded to a neck that continued the nice flaring the vovlo tb had. All welded together. This mod got me 5 more horses at the rear wheels over the entire rpm range.

QUOTE (Krieger914 @ Feb 11 2006, 03:50 PM)

This mod got me 5 more horses at the rear wheels over the entire rpm range.

"real" 5 hp gain (dyno or other test metod) or seat of the pants "feel" ??

I prefer the "glared at by the guy on the tractor" method! Dave's car is F A S T! Can't wait for my next "annoy the neihbors" scare ride. Also known as the "Hey, wasn't Kev right behind us?" ride!

You know Dino, I've been staying away from that road.

The exhaust note on my car is "distinctive". Today I had an experience that was sad and kind of funny at the same time. My son Gerry was driving and I was sightseeing. He was really taking it easy so the car wasn't real loud but, a blind guy was walking on the side of the road towards us. When I see the white cane I kind of thought "utoh". Anyway, probably 30 feet before we get to him he started heading for the hills. As we passed I watched cause I was afraid he might fall. He was fine so we kept going. I hate to muffle it more but maybe I should.

Dave

The 5 hp gain was measured on a dyno at the rear wheels. Sorry I'm so slow. I just started a new job and have been working my ass off. I still have the adapter plate I made and would consider selling it. Also to note, I originally started with a stock 2.0 tb that I bored out to 48 mm with a custom throttle plate. I did not dyno this set up, but it worked well. I did realize a significant kick in the ass when I changed to the homemade adapter /volvo set up.

Dave, I like the look of the data log.

You look to have the AFR nailed. Mine is much more variable.

I also have a similar spike to the CHT log. Thought it might be some kind of noise?
I guess it is only used for warm up and I have it biased higher.

are you using the LM1 for your o2 meter?

Herb

The flucuation in the CHT is because it gets warm enough to bump up against the last value in the lookup table (.inc file) which is a sensor failure value of 170 degrees. I'm sure it is the result of the fact that the program was designed with water cooling in mind and we push the limits with air cooled stuff. As you said no harm cause it doesn't enter the fuel calculation at 170 degrees.

I have a TechEdge and it's been great. Since I posted this I leaned out cruise a little more and I'm starting on acceleration enrichment. I'm going to try a new version of AE that uses RPM as a variable for the enrichment when I mash it.

Dave

I'd like to add something.... This camshaft is not a typical cam, and was designed especially for this combo, with stock runners with this CR and head work. To date I have found only two camshafts (dave has tried them both) that will work with this arrangement correctly, and I have tried 5 more and 4 different CR values.

Don't be mistakened than any generic combination of parts will provide good VE or a broad powerband when adding this much displacement- I have been taught thats certainly not the case.

I have built about 1 dozen engines as a variant of Dave's combo (mostly only corrected for altitude and climate as variances) and they have all worked very well with the stock plenums and runners.

Last year I spent about 5 weeks on this one project and got a ton of myths busted and found a few weak points at the same time.

Don't think that a generic combination will provide the results (especially tunability) that Dave has gotten, thats not the case at all.

Its not rocket science, BUt it does require venturing into the 4th dimension with a head strong attitude and the willingness to take risks that might require a cam swap- not fun work for a guy that doesn't like spending money.

I love data and attain it so others don't need the guesswork!

For you guys looking for more throttle body and using MS or some other aftermarket FI system let me know I have a Ford 65mm TB from a Mustang. I doubt I will ever use it. I also have several 58mm, 62mm and 80 something from a V8.