What valves do I need to support my Non-PI Boost application?

[Back2Mustangs]

Already searched and I'm not finding anything that answers my question.

I'm building a motor for twin screw boost and I'm looking at all these different kinds of valves out there... How do I know which ones I need for my application?

>I'm using stock 96-98 Non-PI heads.
>No porting/polishing.
>I may push up to the 14 psi mark

...So with that in mind, do I need any kind of spcific valve (stainless/titanium) above and beyond just new OEM-spec valves. I was thinking just a regular set of Manley valves...?

 

[46gtsblown]

I highly suggest that you contact Jonny Langton I think that's how it is spelt any way everyone knows who he is.
I would also suggest that you use P&P NPI heads, the valves and springs that the porter recomends and keep the boost to 10lbs. This is to reduce the chance of detonation. Lifting your heads when the motor detonates is a royal PITA I have done it twice and on the second ocassion I installed the head combo above and cured my detonation. Unless you enjoy replacing head gaskets keep it sane and safe.

Dwayne

 

[Dope 97GT]

those npi heads are really gonna restrict your flow and it is not really a great idea to use them with that much boost along with the cams and npi intake. Check out the thread that is also in the tech section which is titled something like 330hp w/ 10psi. Not much for that much boost because of the restrictive npi setup. Maybe P&P NPI heads and a pi intake and cams then you could run less boost and be more worry free while gaining way more HP.

 

[VicRattlehead]

I was thinking just a regular set of Manley valves...?

manley good choice, my nephews inheritance depends on you.

 

[DropTopPony]

you will see nice gains by just swapping the stock PI valves in...i don't know the valve size off hand and i'm not home to reference any build books..sorry. I would definately get your heads ported while they are out...

 

[stangGT97]

those npi heads are really gonna restrict your flow and it is not really a great idea to use them with that much boost along with the cams and npi intake. Check out the thread that is also in the tech section which is titled something like 330hp w/ 10psi. Not much for that much boost because of the restrictive npi setup. Maybe P&P NPI heads and a pi intake and cams then you could run less boost and be more worry free while gaining way more HP.

the motor is being built for use w/ a positive displacement blower, so the NPI intake wont be a factor. The NPI heads will flow just fine with a port job and blower cams. Not sure why you would do anything less if sticking with the NPI heads though

 

[Back2Mustangs]

The plan ->

Bottom end =

Teksid block
15cc Diamond Pistons
H-beam rods
Cobra steel crank
Windage tray
*Debating 7qt oil pan or just keeping stock 6qt(any input?)

Guess I'm needing to have the block grooved for the wire rings, and going with copper gaskets. ARP bolts where ever I can use 'em.

Top end =

NPI heads
Blower cams - Undecided on specs/brand/custom grind
Patriot Perf valve-spring kit
Kenne Bell Twin screw 2.1L

I don't want to pay hundreds of dollars to get the heads P&P'd because it doesn't seem like the power gain would be enough to justify it. I mean I could go ahead and buy stage III patirot heads or do a 4-valve swap, but I think I can get the numbers I want without all of that extra work. I've always looked at it like: If the blower is forcing the air through the runner, its getting in there no matter what. Somebody correct me if my thinking isn't totally logical on that idea.

I'm aiming for above 600HP at the flywheel using these NPI heads, and if P&P'ing is mandatory for me to reach that goal I need to know now.

I'm not sure that I can get those numbers with only 9psi without 32-valve heads. I've read tech articles that claim over 600HP with 9psi on 2-valve heads, but it doesn't seem to be very common. I just assumed that I would set my sights on the 14 lbs. pulley, build the internals strong, the valve-train to handle it and see what that gets me on the dyno.

Please let me know if I'm crazy. This is the first time I've done this. Wish I lived closer to Modular Powerhouse.

 

[Gearbanger 101]

You’re going to spend all this money on the rest of the combination, then cheap out when it comes to cylinder heads?!? Those NPI heads are gonna kill you in stock trim. Unported you're not going to see anywhere near 600hp. Heck, 500hp is even going to take some work if you don’t plan on porting the heads.

The blower can only force so much air into the engine before even it is backed up and overcome with restriction. The small ports and shrouded combustion chamber of the stock NPI castings are going to do nothing but bottle neck all of that incoming airflow. It’s not going to take in the amount of air you need and won’t be able to expel the amount it does take in efficiently. Sure you're going to see plenty of boost on the gauge, but you're not going to be turning the kind of power figures you want and you’re going to create a pile of unwanted heat in the process.

If you absolutely must stay with the NPI heads, then have them sent to Renagade Racing to be ported. Swapping out to a set of stock PI valves should do you fine for 600hp, but moving much beyond that and you’ll probably want something a little more durable to take the heat. A good set of custom ground cams is going to be necessary as well. A set of off the shelf bump sticks aren't going to cut the mustard.

Another think to consider is that Kenne Bells new 2.1L compressor is not very well suited for those kinds of power levels, regardless of what Kenne Bell claims in their advertisement. Pushed really hard, you might see it, but you’ll be straining the compressor to the limits and you’ll need to run a steady diet of race fuel to boot. You’d be better off looking around for an old 2.2L Autorotor design, or one of the big bore 2.6L’s to make that kind of power efficiently. If smog control isn’t a problem, you might even consider the Allen Superchargers “Race Kit” that utilizes a Whipple 2300AX as it’s compressor of choice.

Another think I don’t see mention of, is an upgraded fuel system. Don’t think 255lph fuel pump and a Kenne Bell Boost-a-pump is going to get you there. You’ll need to sink a few bucks into that if you expect to make that sort of power without blowing than nice new engine of yours to pieces. Then you’ve got to start thinking about ignition upgrades….

When all is said and done, I hope you do realize you’re looking into the neighbourhood of a $20,000 motor, blower and supporting components combination in order to reliably sustain the kind of power levels you want. Is it really worth that much to you?

 

[DBMSTNG]

why on earth take the engine apart, build up the bottom end, then use stock non-PI heads?? you can find stock PI heads for as little as $300 a pair if you look.

 

[Back2Mustangs]

When all is said and done, I hope you do realize you’re looking into the neighbourhood of a $20,000 motor, blower and supporting components combination in order to reliably sustain the kind of power levels you want. Is it really worth that much to you?

First let me answer the question you closed with: Yes, its worth it. I'll be able to put together the exhaust, fuel and spark along with the entire engine & blower setup for nearly $10K, but I couldn't do it without friends, hook-ups and being an anal shopper. I have no doubts that $20K is a completely reasonable retail estimate, but even if it did cost me that much it would still be worth it. I have sentimental reasoning...so rationallity is out the window on this project. ...And pushing the envelope of the NPI heads just seemed like a good challenge.

Now, let me say that you are my hero, Gearbanger 101. You never fail to answer any question with a clear and logical response.

What you say makes sense... I actually had a set of PI heads, but they were Windsors and I wanted Romeo's so I sold them. Following your advice I'll ditch the NPI head campaign. If I'm going to buy new heads I think I'll just go ahead and step up to 4-valve. I'm aware that 500HP NA can be had with 32 valves so I should be able to reach my goal with a safer/lower amount of boost. And a pair of 4-valve heads only weigh 35 lbs. more than the NPI's, so the tubular k-member and a-arms, coupled with the aluminum block, will still help to offset the additional weight of the blower and heads. I can make due with Patriot Performance 4-valve castings and valve-train(Unless you think Renagade Racing would P&P a set for less?-please give me more details) and I'll consult MPH or VT for custom cams.

I guess this nix's my valve question. I appreciate all the input from everyone.

 

[stangGT97]

In boosted applications, the power gap between the 4V and 2V heads really narrows. You should look into a set of ported 2V PI heads w/ a set of blower cams. This will not only flow more than enough for the power levels you're looking for, but will also simplify your build and shave weight off the front end.

 

[Gearbanger 101]

Following your advice I'll ditch the NPI head campaign. If I'm going to buy new heads I think I'll just go ahead and step up to 4-valve. I'm aware that 500HP NA can be had with 32 valves so I should be able to reach my goal with a safer/lower amount of boost. And a pair of 4-valve heads only weigh 35 lbs. more than the NPI's, so the tubular k-member and a-arms, coupled with the aluminum block, will still help to offset the additional weight of the blower and heads. I can make due with Patriot Performance 4-valve castings and valve-train(Unless you think Renagade Racing would P&P a set for less?-please give me more details) and I'll consult MPH or VT for custom cams.

I don't think ditching the NPI heads all together is necessary. If you're combination is already built up with them in mind, then go ahead and use them. Just make sure they're capable of flowing the amount of air you need them to. Remember, going with a set of PI, or 4V heads is going to change your compression ratio again which you might not want.

I realize that cost may not be a big issue for you, but if the DOHC head swap is in the cards, you’re going to need the 4V timing/valve cover(s), accessories, brackets, headers, etc, etc. Not to mention cams are going to cost you twice as much as they will with the 2V castings. Lets not forget the need to upgrade to the more expensive 4V manifold, cooler and supercharger set up to bolt on top of those heads. For what it would cost you, you could easily spend 1/4 as much just having your NPI's ported and prepped....and both set ups will get you to where you want to be.

A general rule of thumb is to take the cost of the major components, then double it by the time you're in up to your elbows in car parts and realize how many little things you might not have thought of initially are going to nickel and dime you to death.

Do a search on here from about 8-months or so back. There was a thread started about Renagade Racing and I as well as a few others posted some flow data and photo to promote the NPI power capability. When ported and prepped in most cases, the NPI castings were actually better flowing than the PI castings.

One other upgrade I might suggest are billet oil pump gears. They’re about $250.00 and they won’t give you, or save you any horsepower, but at the level of ponies you’re going to be producing, they’re certainly one of the better insurance policies you can invest in against engine failure in the event that heavy engine detonation occurs

 

[Back2Mustangs]

Ok, so I wasn't totally wrong...

So if the gap of power between 2 & 4-valve narrows with boost then I suppose my idea of the air getting in there no matter what wasn't totally wrong. The reason that I decided to just use what I had in the way of heads was because of Kenne Bell's results with the 1.7L on PI vs NPI heads. Their numbers seemed to show that the NPI heads responded a little better to the blower so I thought why swap if what I have is good enough.

All the extra's associated with the 4-valve heads was why I wanted to stick with 2-valve heads to begin with. Even though I have to use a 4-valve timing cover for the Teksid block, and all of the fuel system and headers are being replaced anyways, I'd still have to have wiring harnesses and new valve-covers and just a bunch of little nickel & dime crap that I don't want to mess with. I'll search for the thread you speak of(Gearbanger 101) and check out the flow numbers and Renegade Racing. If merely porting and polishing the NPI heads will cure the "bottle-neck" then I'll go that route. If I do go with PI heads then I'll have to change out pistons, which is just one more reason to try to make the NPI's work for me.

And thanks for the tip on billet oil pump gears. Its the little things which no one tells you about that wind up costing you more time/work/money down the road when it breaks. Any other suggestions you have I will more than welcome.

And I'd actually like to hear some of your reasoning for promoting the Allen kit over the Kenne Bell. I decide on the Kenne Bell above the others for only one reason: Thats what most of the twin-screw cars seem to be running, so they must be doing something right.

My main concern with the front half of this car is to drop as much weight as possible and keep excessive under-hood temps to a minimum. I've had good luck in the past with heat-wrapping ceramic headers. I never experienced any of the problems that some people warned me of with rust/moisture. So I'll give these long-tubes the same treatment to help battle under-hood temps.

 

[Gearbanger 101]

And I'd actually like to hear some of your reasoning for promoting the Allen kit over the Kenne Bell. I decide on the Kenne Bell above the others for only one reason: Thats what most of the twin-screw cars seem to be running, so they must be doing something right.

Not really promoting one over the other, just giving you another alternative to the cookie cutter set-up that the Kenne Bell faithful promote. Letting you know they aren’t the only game in town when it comes to making big 2V power when a screw compressor is in question. Were it my choice, I'd go with the Allen, but not because it's necessarily a higher quality kit over the Kenne Bell unit. One of the main reasons would be cost. The Allen Race Kit is going to run you about 1/2 the price of the Kenne Bell (2.2 or 2.6L) set when all is said and done. Going with the large displacement Kenne Bell kit is going to require an aftermarket hood, where going with the Allen and standard intercooler won't. You'll be responsible for your own throttle cable, cruise control bracketry and as well as fuel system components, but otherwise that's it. It’s also not smog legal, but neither is the Kenne Bell.

Another nice feature I like about Allen unit is the fact that the airflow only needs to make a single 180* turn before entering the cylinder heads. All other positive displacement kits require at least 2-180* bends before entering which causing added back up and restriction. When all is said and done, this isn't really going to matter in your case, since both blowers will easily support 600hp, but it's food for though.

Again not knocking the Kenne Bell kit. It’s a really nice unit. It’s just not the only nice unit as a lot blind MPH and Kenne Bell followers might have you believe.