Ok guys, Well, i'm not going turbo anymore, just too much money so i sold a bunch of stuff which you may have seen in the BST section. So I am rebuilding another block stock bottom end since mine now has pretty rocky compression numbers. Here are the mods i am planning.

Crower stage 2's with all supporting mods of course

P&P my stock head which is coming along very well

Bore and match TB to mani 55mm

Fidanza light flywheel

CM stage 1 or 2 clutch

Unorthodox UDP

Shaved Head for close to 10 5 1 compression

Symtech manifold plenum spacer

Hondata manifold spacer

AF/X ECU

ANd of course all the legal bolt-ons so the cops don't screw me when i get my hood popped. (California sucks)

My only question is, will the stock bottom end be ok to 8100rpm with that afx ecu? Valvetrain is all built so the head is fine, just not sure about the bottom end.

Any suggestions or advice would be greatful
Thanks in advance.
Cameron

The Mopar PCM's for Neon's let them rev out to 7600rpm.

My DOHC Neon used to hit 7600rpm quite often with no ill effects.

Hmmm..... that sounds good. Can't see why another 500 rpm's would hurt. Thanks Tim

Nice. All motor is a lot more fun than the hey-I-just-want-400hp-like-every-other-choad-on-the-internet turbo crowd will ever know. :thumbsup

A couple thoughts.

Don't worry about compression ratio (CR). It's 4% for each point CR. You bump a 140bhp engine up 1pt and you net about 6bhp. For the money and effort involved in just stepping up to 10.5:1 CR, you're not looking at much in the way of gains.

In just about every instance I can think of, the benefits to bumping up compression a point (or less) are marginal at best. Why do some people do it? It's a good idea if you'd like to use the engine as a foundation for more extensive future modifications like a >75 shot of nitrous oxide or a responsive, low boost turbo setup.

Besides, shaving the head enough to affect CR is going to mean your factory timing marks are no longer correct due to the camshaft centerline being moved closer to the crankshaft. It's a clear degree more effort for you which doesn't necessarily provide gains (less than 6bhp).

Now, for headwork, it's easy to get caught up in the hype to go for the full race port since you aren't doing anything to the bottom end. Here's the catch. You know all that theory on how to choose exhaust piping diameter? Same thing applies to the engine.

For NA top end power, VOLUME is key.
For NA low- to mid-range torque, VELOCITY is more important.

You open it all up hog wild, you gain VOLUME, but you lose VELOCITY (down low).

Consider this scenario:

Dude throws a 60mm TB on a hogged out SMIM with a phenolic spacer between it and the head. The head is hogged the fuck out. Full race port, +1mm stainless valves intake and exhaust, fully radiused valves, maybe a little bowl work, a set of Crower 3s,and then a mass market shelf header on the hot side.

Sweet setup, right? Sounds like something Mark was running about 2 years ago. :P Guess where this engine starts to pull. Around 4000rpm. That's where. Is it still pulling at the factory 6000rpm redline? Yup. Is it still pulling at 7000rpm? Yup. Is it still pulling at 8500frpm? Probably. (C2s were.)

Sounds b-fucking-a, don't it? It is. Until you're stuck in stop and go traffic in it. The car ahead of you takes off, the gap opens, and the jackass in the lane to your right is hellbent on getting just one spot closer to the front of the line. Unless you're sitting on about 3700rpm, he's got that spot.

Why?

VOLUME VERSUS VELOCITY.

Ever forget you're in 5th, find yourself giving it gas at about 40mph and the engine turns into a grumbly little bitch? That's velocity in action. Same thing happens when you open up the flow in pursuit of volume.

You get your low- to mid-range torque by focusing on VELOCITY. Stepping up your TB and cleaning up the head to flow a little better is a good thing. Don't get me wrong.

Bolt up that 55mm TB.
Have the factory IM cleaned up, gasket matched at both ends.
Bolt up a phenolic spacer to increase runner length (not cool the IM).
Have the intake ports cleaned up a bit.
Keep the stock intake valves, but go full radius on them.
Maybe go with larger exhaust valves.
Maybe open up the exhaust ports a smidge and clean them up.

When it comes to getting air into your NA engine, you want that air being drawn in at as high a velocity as possible. Right off the line, through at least 3500rpm, because that's where you're going to use the engine the most. Will you lose a couple ponies off the top by not hogging things out? Sure, but how often do you use those?

Just my thoughts on NA headwork for a daily driver.

EDIT: OH yeah. And I almost forgot. It might be REALLY FUCKING COOL to get the stock bottom end balanced out to 9000rpm or so to match the upgraded valve springs you'll be buying to go with those cams so you can STILL wind that pig out beyond redline.

The AFX ECU is a good call, but for the price, you could get better results from an MSnS install. Done properly, I think you could get away with it in California too.

Consider an adapter harness. Go to the junkyard and trace the injector and coil pack harnesses back to a main connector. Cut them off before that connector. Then terminate your MS harness with that OEM connector. Now you'll have 2 of them in the engine bay - 1 for the ECU and the other connected to the MS. A week before smog, you just swap it. Just an idea I was working up for smog over here in Phoenix.

Finally, give some thought to a true LTH. Do some reading through old posts here for specs. There are a small handful of fellas who can make one for you. You will probably have to send them a stock header and downpipe and you'll pay a couple bucks more than you would for that shiny Ebay turd, but you *might* pick up 20-30whp if you get the numbers right.

You'd pay extra to have your head shaved to bump up the CR a bit for less than a 6hp gain. You'd pay extra for a race port over a street port. You'd pay extra for oversized valves all around. Why not use the money you would have spent on those overkill services on getting yourself something TRULY nice that you should REALLY notice and that most people DONT HAVE?

Just a couple thoughts.

(Goddamn. This post felt good. I miss engines.)

Lot of good info there man....enjoyed reading it!

Originally posted by DR1665
The AFX ECU is a good call, but for the price, you could get better results from an MSnS install. Done properly, I think you could get away with it in California too.

I like your style Driggs.

But the only way to get away with a MSnS in Cali is to straight uninstall it when you go to smog. They connect to our OBDII ports out here.

Yeah, looks pretty cool. I take it you are talking about a rebuilt bottom end (but to stock parts and specs).

Pistons and rods should be fine. Go with 2.4 valve train. Cheap enough to get and better for the top end (quieter too).

That should be a nice little build.

Wow man, nice post. Lots of good info there. The thing is i have to have the head worked on because the headgasket was a little iffy on it and around some of the water jackets started to eat into the head surface so i have to get it filled in and resurfaced so why not shave it a bit ya know? every little bit helps. I was thinking about MS, but honestly I'd rather have something that is just throw on and go. If i was going to go MS i would make it a full stand alone but i dont really want to go that route. I want everything to look legal under the hood. Cops are crazy here. They have laptops and pull up pictures of your stock engine bay and compare. lol it sucks. My friends car looked stock but when they did that, they busted him for all kinds of shit.

As for the head, I already have it in the car now. It pulls pretty decent but that head is a pretty shitty P&P which is why I am porting my stock one myself. Exhaust ports are smooth as glass, combustion chambers are polished, intake ports are gasket matched and will do same for IM. All i have left is the throats on the head (the harder, more time consuming part.

That is also a good idea to have everything in the bottom end balanced. And for mark, yes stock rods, pistons, and specs. Any idea of a ballpark price for balancing?

Head hardware are as follows:
Crower 2's with springs and retainers, PT cruiser rockers and lifters, stainless std size valves.

I think i will just keep my stock valves on this head i am working on and get a valve job done. Just to prevent more down time. I just want to get everything at once (as far as internal engine parts go. As far as the header, intake, and UDP, those can be put on later.

Thanks again for all the input. I look forward to seeing what else you guys have to say.
Cameron

damn driggs. lol

ya I know he had a field day. lol but that's why I like this forum. all the people that know everything share it. they don't just read and skip it. driggs, terry, and mark are always here for everything. others too. small enough community to know most people by name but large enough to find everything you need.

Every once in a while, I get jiggy with it.

Haven't really done anything engine/performance wise on a car in about 3 years now. Just a K&N and a MBC for me. The rest has been body repairs. :(

Ok, a few more ideas. I'm trying to think of some ideas for the intake manifold other than the spacers. I was also thinking of having a plate made to extend the runners even further more than just the spacer alone. Maybe a 3/8" plate or so. My friend did this on his accord and I did notice a pretty substantial gain.

Another idea, would it be a decent idea to relocate the air temp sensor to actual intake itself? would be more accurate and show the ecu the air is cooler than it would on the manifold.

Any other little ideas to squeeze a little more out of it here and there would be great.
Thanks

That's actually a good idea. Makes sense to.

Originally posted by halfasss101
I'm trying to think of some ideas for the intake manifold other than the spacers. I was also thinking of having a plate made to extend the runners even further more than just the spacer alone. Maybe a 3/8" plate or so. My friend did this on his accord and I did notice a pretty substantial gain.

Define substantial.

Changes in runner length are going to affect low- to mid-range torque more than anything else. Granted torque and horsepower are related figures, but the only real way to tell would be to dyno before and after.

If you've got no means of tuning the engine, see if the local shop will let you buy a 4-pull deal or something, where you would make 2 pulls one day and come back later in the week to do the other two.

With a mod like this, you're going to want to see where the power/torque curve changes. These things can be tricky. Maybe you gain 2whp up top, but pick up 20 in the mid-range. You never know unless you put it on the rollers.

Do some research into Hemholtz resonance or whatever it's called, then see if you can't better determine how to size this space. I think it's a good idea, but if you're going to go for it, you might as well do it right.

Have you thought about doubling/tripling up on phenolic spacers? What about picking up a blank flange or two? You're going to have them all gasket-matched, right? How far can you go before you run out of fastener? Where are you going to source new hardware to bolt this all up?

Originally posted by halfasss101
Another idea, would it be a decent idea to relocate the air temp sensor to actual intake itself? would be more accurate and show the ecu the air is cooler than it would on the manifold.

Define accurate. ;)

If the ECU is relying upon IAT data to determine fuel mixture in the combustion chamber, how accurate is that data going to be if you move the IAT further away from the combustion chamber? How accurate will your fuel trims be if there is a variance in the IAT reading and the actual IAT at the intake valves?

Good point on the IAT. I was thinking about doubling up the spacers, but shit, thats almost 200 bucks just for 2 spacers after shipping. Can have my friend make a plate for me at his shop for next to nothing. Going to look more into it and do some more research. Of course everything will be gasket matched. Would be pointless if it wasn't right? lol Going to take some measurements of stock manifold tonight and do some figuring and try out that hemholtz