Pelican Parts Forums - Wayne's Answer to the Question: What engine should I build?

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Quote:

Originally posted by NevenM
As you can guess I'd advocate Megasquirt EFI with the original intake for the following reasons.

I'm not sure how hot a cam you can run using the original CIS runners and MegaSquirt.

-Wayne

Quote:

Originally posted by 125shifter
Wayne,

After looking at your engine choices in the book, I wonder why the turbo engines are relatively stock. I.E. stock cams and CIS. I would think people that are building a turbo engine have a larger budget. In the next printing how about have a turbo set up for mid range power and a turbo set up for top end power. JMHO.

It's a pandora's box. Anytime you modify a Turbo, you're getting into more wear on the engine, and typically bigger $$$. Plus, there are no real easy Turbo upgrades. Some changes (like SC cams, etc), but nothing that will buy you a great amount of HP. Changing turbos themselves will alter the boost-on RPM, but then you sacrifice power elsewhere. The only way around the turbo lag problem is to install a 2nd turbo like they did in the 959.

So, keep it stock and reliable, or spend $$$ and decrease the longevity of the motor. Also, you hurt the resale value as soon as you start modifying a Turbo, because no buyer really knows what abuse the motor has taken...

-Wayne

Wayne

As hot as you like, As you know the Cam limitation is not the CIS runners but the CIS metering system which does not like pulsing in the air flow. It would not be as free flowing as ITBs but much better than CIS. Which is a point, You would get some performance inrease in a CIS to EFI conversion simply because you are removing the CIS metering system which impedes air flow

Neven

Quote:

Originally posted by NevenM
Wayne

As hot as you like, As you know the Cam limitation is not the CIS runners but the CIS metering system which does not like pulsing in the air flow.
Neven

That's not true. The CIS system is not an independent throttle body system, and cannot take a really hot cam, otherwise the engine will never idle correctly. It would be the same as running a hot cam with the 3.2 runners, which just doesn't work.

I just talked with Rick Clewett about this the other day in response to a question someone had.

-Wayne

Quote:

Originally posted by NevenM
Wayne

As hot as you like, As you know the Cam limitation is not the CIS runners but the CIS metering system which does not like pulsing in the air flow.

Not exactly. There is some discussion of cam choices/limitations with single plenum here.

Tom

Wayne

Ok its not entirely true, but then again does any engine with a 906 cam idle smoothly? But as I also pointed out you could then put in a set o.5f modified MFI ITB's for less than 1K which is much less that the 3+K required for a TWM 3006

Neven

Quote:

Originally posted by Wayne at Pelican Parts

Plus, there are no real easy Turbo upgrades. Some changes (like SC cams, etc), but nothing that will buy you a great amount of HP. Changing turbos themselves will alter the boost-on RPM, but then you sacrifice power elsewhere.

IMO not true. I installed headers, a large intercooler (that is for sale), 1 bar spring, and a K27 and got over 100 more hp out of a 3.0l 930. I think that is a lot for a few boltons.

So, keep it stock and reliable, or spend $$$ and decrease the longevity of the motor. Also, you hurt the resale value as soon as you start modifying a Turbo, because no buyer really knows what abuse the motor has taken...

I also don't think that is true.

-Wayne

Quote:

It would be the same as running a hot cam with the 3.2 runners, which just doesn't work.

Could you elaborate on this? Is the limiting factor air flow?

Quote:

Originally posted by echocanyons
Could you elaborate on this? Is the limiting factor air flow?

It is the single plenum, See the link I posted up the page a bit.

Tom

Musta missed it before but I gave it a read,

Thanks Tom