So... I have a stock block B18C-R with Toda replica header's, Bpi Velocity stack SRI, and 3 inch exhaust that made "195whp 136tq" peaking right at 8K. I have read online and seen a couple dyno's where the P30 out performs the P73 up until 8K, the two examples are a B16 and another B18C. The difference between these motors and mine is simply power, both of these examples made roughly 170whp. Does anyone have experience with the P30 outperforming the p73 on higher HP applications? I autoX/track my ITR and am looking to add a bit of midrange for cheap and figured a P30 might do the trick. Not looking for power after 8k as it would benefit me to keep revs conservative to further preserve the block. Any advice/info would be appreciated.

 

I use a Ported P30 along with 70mm TB and it Peaks at 9100 with BloxC's, So I'd say it carries power well over 8k depending on the setup. It won't be cheap though to run a P30 and see good results. You'll have to Port it, you'll definatly need a larger TB and you'll need a tune because the whole thing will be way off.

 

Well.... on my current setup I already peak at roughly 8k WITH a P73. Since the P30 is said to make the most average Hp before 8K is there a good chance I will see gains around the 5000 -8000 rpm range by just bolting a UNPORTED P30 on my B18C-R? On lower power engines it has been proven that P30 is better under 8K, does that carry onto a 200whp engine as well? If so... will the P30 still be useful with the addition of some Pro1's/BC3/or S2S2? (still mainly under 8K).

 

I think with cams any intake will carry power where ever the cam wants to try to, but the real question is does the P30 carry power to 9100 as well as a P73 would ( I think not? ) on your particular setup, and would the P30 outshine a p73 on your setup under 8k? those are the question I'm trying to answer.

 

alright here is my input. i have a lsvtec about 12:1 using itr cams. i went back and forth between portmatched p30 and sk2 pro (pretty similar to p73 slightly bigger plenum i think.) i settled on sk2 based off fuel consumption and butt dyno. i have the feeling that you might have a bit too much power for p30 but who knows.

 

Thank you for your reply, what are you revving your car to?

 

I am under the impression that the S2PRO has longer runners than the ITR among other things but i might be mistaken here someone else could clarify.
Also what TB ? TB size plays a rather importan role when the plenum volume is on the small side.

 

Carrying Power and Peaking are two different things. Yes it probably will provide more midrange to answer your question, Cost wise the hp gain will not even worth the remaping cost imho.

 

P30 on your engine RETUNED CORRECTLY will own a P73 everyday you will need to move the cams around to get the results your looking for,I would stick with the OEM cams for AutoX the Pro1 will move the power band into the higher RPM's

 

i second daves statement!

 

Pro1's on a B16a and using a P30 made better AVERAGE TORQUE than what you where using.

 

Would the same hold true for a "stock" B20 vtec? (stock block, stock 1st gen B16 head)

 

On a STD B20Vtec build I find the P30 with a 68mm TB well designed SRI with V Stack and long tube replica style header works for the best average torque curve upto 8000rpm.

 

Good **** Uncle Dave, that's more or less what I wanted to hear. I dont care if my p73 peaks slightly higher if its gets its *** kicked the entire way there. Any dyno graphs by any chance?

 

My experience with the Pro1's is that they may (slightly) move the power band up BUT on my last I/H/E B18C i gained an average of 12whp from 5000 till 7800 and peaked quite a bit higher as well peaking at about the same time.

 

Mind you the b18C arrived to the shop on a basemap so the gains may have been inflated but you get the point.

 

Great info! But wow that's a large TB. And would you use the big tube header vs the standard?

 

I would say yes and yes.

For an auto cross or short track car limited to displacement, or the owner doesn't care to swap motors, I think the P30 IM would be the way to go - ported or not

 

"STD B20Vtec" meaning oem cams Unc??

 

FWIW my 82mm GSR w/ PR3 pistons fell on its face right at 7800 using a stock P30 IM and maxbore 65mm tb w/ skunk2 tuner stage "1.5" cams. They were a custom grind. By the time 8k hit it was on the downfall in a hurry. So for best mid and performance up to 8k I'll agree, but anything after that its worthless IMO. I never got a chance to run an ITR IM before it was stolen.
With that said there is a reason Honda designed that intake for a 1.6, and other intakes for the 1.8's. Food for thought.

 

Wow... Thanks for all the replies guys. In my case since the car is DD and autoX'd I think the P30 will be great, hell even if I didn't gain anything and it simply moved my power band earlier I think it would be worth it for longevities sake. I know I know, type R motors can rev past XXXX amount and people take them to "9k all day" but after losing my fully built C5 over something seemingly trivial, you can say I'm paranoid. If anyone has anything to add keep it coming, more examples of different setups utilizing the P30 would be cool, but overall thanks for the help ::

 

a while ago I swapped out the p73 im for a p30 mani on my stock b18c-r, I noticed it has better low end pull, and I didn't really notice a big difference up top. Sadly I didn't dyno it before and after, so no graphs.

 

With a B20Vtec I find the small tube to work very well with b16a/B18c2 cams if going ITR cams I would use the big tubes or the Logic replica header or the Toda Replica.Small plenum needs BIG TB big plenum needs smaller TB to keep the air speed up the the manifold entry.

 

Yes OEM cams the minute you put a S1 type cam in these engines you will need to rethink the manifold to suit along with your header.

 

I even think once you put ITR slugs in it you get into the same predicament. 2L @11.5CR is a lot of air movement compared to the 1.6L @10.2 it was designed for.