12V V6 on aftermarket ECU

[CorseChris]

Thanks for the tip on plugs Greg - I'll swap them out ASAP.

[CorseChris]

Minor update....fitted the blower belt and ran up the motor yesterday. Belt run works fine...but what a racket! I was expecting the blower to be noisy on open inlet/outlet ports...but wow!

Assembly of the belt is a real pig, but I've figured out the method now, so next time will be easier.

[Bill-Sims]

Could very well be your exhaust--I gained 25 hp just by changing out the glasspacks behind my headers!

I also run an Eaton supercharger. Now have it at 8.5 psi with S pistons...obviously on race fuel.

[Bill-Sims]

Great job of combining these parts from various sources!

And beautiful car, too.

[CorseChris]

Cheers Bill.

I'll be using water/methanol injection, so from your info of running S pistons @ 8.5psi boost, I reckon I should be safe on pump gas with my setup. All coming together now....

Exhaust will be sorted at some point, but it'll have to do for now. So much to do, so little time & money to do it all.

[Bill-Sims]

Beware! I am running 112 racing fuel, not 93 octane pump gas. And a water-to-air intercooler. Plus my car is used only for autocross, with average run under a minute, and at full throttle maybe 15 to 20% of time.

I destroyed an almost brand new 3 liter engine 3 years ago with S pistons and 6 psi boost during a run on a hot day. Was relying solely on an Aquamist 1S water injection system that was tuned on the dyno to put in as much water as it could without quenching the power when I first put down the throttle.

I had a part of the course where shifting really wasn't going to be a good option, so I ran to 7000 rpm (rev limiter back then was at 7400). Since I had bigger injectors than OEM, but not huge ones, the fuel surely went lean (had seen on dyno that system starting going toward lean above 6100). Engine apparently suffered high speed detonation and destroyed #2 piston in short order (less than a second, as I never heard anything except the explosion). Large chunks of that piston then dropped down and twisted #1 con rod.

A couple of watchouts here: 1) If you rely on water injection, go for a sequential system and have a light that lets you know it is working (and keep the reservoir with water!); 2) use high enough octane.

Before each of my runs in warm weather I run the pump and fan for my intercooler and get the intercooler cooled off (with engine turned off). That way my air/fuel charge is nice and cool. Yes, that gives more power, but most importantly deters detonation.

One last thing: I threw away the Zat Pandora's box and L-Jetronic and installed a programable Haltech E6X. Then with new engine spent alot of time and $$ on dyno setting up the engine. Was especially careful of high speed detonation.

[Bill-Sims]

I should add that the engine now has 550 cc injectors.

Idle is just fine--then again, my "idle" is about 1500 rpm! I run cold plugs, and biggest challenge is getting the engine warmed up to temp before runs. A slow idle would surely foul the plugs.

[CorseChris]

I'm certainly concerned about detonation - hence fitting the air/water cooler and the water/methanol injection. I'm happy the injectors are going to be big enough, and getting timing and fuel right isn't an issue with the ECU I use - it's all down to the basic 'physics' of the setup - will it work or won't it! There are too many variables that I can't answer to make anything other than a guess at the boost I'll get. It won't be more than 8.5psi and could be as low as 6 at lower revs. Really don't know, although I'm tempted to run it up off load and find out.

I plan on driving it to the rolling road aspirated then bolting the neccesary bits on when I get there. I still want to try and do a couple of power runs first though - as it arrives, for reference, then add one of the old moving flap AFM units and do it again just to answer an old question.

[ToonRboy]

Hey Chris,

I thought the numbers on your engine as it stands look quite good. Very different to what it would look like running the Dino 246 engine (195hp/~150ft.lbs.@7600rpm).

I would be worried about blowing-up that nice motor too. Too much static compression IMO. If that's an M62 blower on there, I'd keep the boost down if I were you. As you can see in this graph, it doesn't flow much more at 10psi than it does at 5.

You definitely have sufficient injector. Is the Haltech handling your spark? If so, I would configure it to retard the spark advance using input (trigger) from MAP. I know Greg uses the Water/Meth to handle this, but it's extra insurance. You'll lose performance by retarding the spark, but blown engines can stand a less agressive curve.

For clarification, here is a pic of what I meant on the turbo thing. Not to rebuke anything said of Lancia history, it seems to me that since the 70's the Lancia Delta HF Integrale, the Lancia Beta Monte Carlo Turbo, as well as the most powerful Stratos -

were all turbo's. BTW - This pic is from a Lancia Beta Monte Carlo.

Best regards,

[Greg Gordon]

ToonRboy:

No offense, but I think you are reading that graph backwards. That chart shows the supercharger flowing less air at the inlet at 10psi than at 5psi. This particular graph, while accurate, confuses a lot of people. Eaton is now going to a more conventional compressor map instead of using these graphs.

Greg,
hiperformancestore.com

Greg

[ToonRboy]

Hey, thanks for pointing that out Greg. I did read the legend upside/down. Thanks for making my point that much more succinct. That is not to say this is the unit that Chris is running. He didn't answer that question. I sure would love to have his torque curve (+ 50ft.lbs the sc brings on the whole curve)!

[Greg Gordon]

Hi ToonRboy, Chris is actually running an M90 supercharger. The M90's inlet flow chart looks just like the M62's chart you posted, just with larger flow numbers.

Don't misunderstand this chart, at an Eaton M90 will put far more air into an Alfa 3.0 at 10psi than it will at 5psi.

Greg

[ToonRboy]

Hmmm, M90 seems a bit big for just 3Liters. For a target of 250hp and 250-270ft lbs of torque, I would think 350-400cfm should do.

BTW - I got that chart from RB Racing. http://www.rbracing-rsr.com/turbo/TurboMaps/M90flow.gif

I think the lesson here is that more isn't necessarily more. Everyone talks in terms of boost and as you said, the flow increases with rpm (at a given boost). However, the charts show that with these types of blowers, flow gets impeded by increase in boost pressure! The fact that it lost only 10-20 cfm is admirable, but by doubling the boost all you did was create heat. And that is my concern here when Chris is already starting with 9.5:1 static compression. At 5psi boost at ~100ft altitude ASL, your effective compression ratio would be ~13:1. At 8.5lbs boost, you'll be at ~15:1.

So I ask, would you even think of running pump gas if you had a NA engine with compression ratio's like this?

[Greg Gordon]

Ok, I think we got lost in the editing. I was editing my post before I saw your response, then you edited your response to my post. I never saw your original response.

Anyway...This is getting complex. To keep things organized I will address the effective compression ratio first.

There are actually a few ways to calculate effective compression, and the charts out there are not all in agreement with each other. I use Jim Steck's chart.

On Jim's chart a 9.5:1 engine with 5psi will have an effective compression ratio of about 10.8:1. That's been well proven to be a usable ratio on pump gas (other charts may show different effective ratios but that boost value and compression ratio are knows to work so the reference number is still a valid baseline). With 10psi this goes up to about 12.3:1 and this become a little questionable, but not impossible.

Greg

[Greg Gordon]

Regarding the airflow issue. I really think you are misunderstanding that chart. A lot of people do, and that's probably why Eaton has replaced this chart with more conventional compressor maps. I hope I am not coming off as being hostel or snooty, I am just trying to clear this up.

With an increase in boost pressure from 5psi to 10psi on an Alfa V6, air flow out of a M62 or M90 will INCREASE by about 25%. The increase in heat offsets a little of this, but not that much. More IS more in this case as it pertains to airflow. The airflow increase happens because in order to increase boost you increase the supercharger's speed. This chart doesn't clearly show that. It's not designed to.

Here are some approximate numbers. If 6000 supercharger rpm gives 5psi on a give engine, that engine will probably need about 7500 supercharger rpm at the same engine speed to get 10psi. Compare the 6000rpm 5psi flow numbers with the 7500rpm 10psi flow numbers for a more valid comparison of airflow.

Think of that chart this way, that it'is showing an increase in boost pressure resulting from a decrease in engine displacement! NOT from increasing boost pressure from the supercharger on a give engine.

Oh, and one more thing, flow out of ANY forced induction device gets impeded as the result of increasing boost pressure. With a positive displacement pump this is actually pretty easy to measure because it results in a decrease in volumetric efficiency. With a centrifugal pump, the effect is essentially the same, it's just tougher to measure because centrifugals are not rated in volumetric efficiency.

Greg