Ported Intakes

[88turbobird]

I just installed a Boport 1.5 cam with roller followers, springs, and HLA’s. The extra rpm from the cam is great. My question is how much am I leaving on the table power wise with the stock, unported intakes? Ideally, I’d have a built, ported head but that’s not an opinion right now. As for current mods, I’m running a GT35R Turbo at 20 psi with FMIC on a pimp ECU. 60lb injectors with 255 walbro so fuel is not an issue right now.

[Stinger]

Well, if you had a ported head the answer would be "a ton" but without a ported head, the flow through the intakes isn't really the problem, it's just that the intakes are designed to make peak power in the 4500-4800 rpm range (long runners) and your cam is designed to make power at higher RPM (which favors shorter runners). So adding a gutted and ported intake would allow the cam to peak where it wants (and the peak would be higher than it is now) but you'll give up a little torque/low RPM power in doing so.

[tutulate]

Please forgive me for intruding in this, Shannon, but what performance can one expect from porting the stock intake without gutting the upper?
Thanks, Howard

[Stinger]

Porting adds flow, gutting allows you to optimize the setup for a higher RPM power peak (which is required for a small displacement engine for maximum performance).

What you'll gain from porting depends on the package around it. A ported intake on a stock head isn't overly beneficial. Same goes for a ported head/intake with a stock turbo, far from ideal as the turbo limits flow though the engine.

The engine is just an air pump. The more air you can pump through it, the more power it will make. To pump more air, you need more airflow (porting, bigger turbo, bigger cam, etc.) and RPM. Whenever you upgrade something, you just uncover the next cork in the system so this is where a well thought out and matched setup makes power. Once improperly sized part will kill power.

[tutulate]

My current setup is a large-valve/beehive spring Stage 3 ported head with a 1.5 cam, ported intake and E-6 exhaust and stock T3 turbo.

My current need is to make sure I can reach the WOT shift of 5400 of the 2004R within the power range.

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[Stinger]

You'll need to dial that in with cam timing (or make the trans shift at a higher RPM which would be the ideal solution as that engine should make significantly more power if cam timing is set to let it peak at 6000 or so).

[88turbobird]

I am planning on buying a gutted upper and ported lower intake after reading this and doing some further research.

Question about cam timing: I used the stock cam sprocket on the boport 1.5 cam. I understand that I can buy an adjustable cam sprocket but could I adjust the cam timing by moving the cam sprocket independently of the crank (I.e one tooth clockwise, etc.) When I installed the cam, I marked the pulleys to ensure they were the same upon reinstallation of the belt. I already had the ignition timing dialed in from installing the pimp ECU.

[Stinger]

One tooth is 19 cam degrees which is too much adjustment. Typically you move the cam 8 degrees or less with an adjustable cam gear. We sell adjustable cam gears for this purpose.

The other issue with using a stock cam gear is that "zero" is no longer zero in terms of cam timing because the cam can be ground with advance ground into it, the head may have been milled at some point, etc. and all of this throws cam timing off a few degrees.

[turboragtop]

Shannon,
Can an engine run decently if the cam timing retarded by one belt tooth?
I just upgraded to an Esslinger aux shaft and in the process I suspect I got the cam timing off by one tooth.
The car runs fine, it just has lost some bottom end, i.e. it used to break the tires loose on a 2nd gear stomp, now it takes an extra beat and then runs great up to 6K.
Is is possible to run OK with the cam timing off by one tooth?

[Stinger]

Yes, it can run OK with the cam timing off a tooth. Put it at TDC and take a look.

The other issue is if you're using a stock cam gear with aftermarket cam, or an aftermarket gear but didn't use the E-bar method to find zero to start with then cam timing will be advanced or retarded relative to what you think it is.

[turboragtop]

Thanks Shannon. I'm going with the E-bar method. I'll let you know what I find.