Performance intake/exhaust options

[The Dark Side of Will]

Apologies for getting into the side-track. :salute:

Has anyone ever clearly identified a single cause for the 4k "wall?"

I think that the way power falls off past 4500 RPM is attributable pretty much totally to the intake manifold. There are a few examples of better intake manifolds (like Trueleo's or the dual plenum manifold) liberating only a few ponies peak but 3-4 times that many at 6000 RPM.

I don't think the car's exhaust bottlenecks will rear their heads until the engine is making a lot more power. I'm wondering if a stock 2.8 longblock with a dual plenum manifold & a well designed set of long tube headers might hit 160 WHP...

[BigRedDeckSpoiler]

didn't you already dyno yours at around 130 whp? He won't need larger then 19 lb injectors eihter on a n/a setup.

The last dyno was 134 whp.
That was through the slushbox, with unported heads, lower intake, and stock cam (albiet with 1.6 rockers.) I thought it should have made more, but it was what it was.

Having said all that...
I never thought the engine ran right.
There was an identical car (Larry Henthorn's), with an identical engine. The chips were even tuned by the same tuner. Mine consistently made 5-10 HP less than his, even dynoed on the same day.

The trueleo, pulley and rockers made about the improvement that I whould have expected. Just that the initial dyno was low, and the upgrades were still affected by whatever was hindering the earlier pulls. (It was still slower than it should have been. Only a quicker "slow" than it had been, previously.)

There was lots of speculation as to what the issue was (Cam? Tranny differences?) But it was all just that. Speculation.

Both of those are out of the picture, now. It seems to be much improved.

As I've said before, we shall see.
Still gotta get the tuning right. Doing my own tuning now, at least the preliminary stuff.

I've gotta tell you...
I've seen some real bullshit perpetrated by "tuners" who are supposed to know what they're doing. People with real dynos, shops full of diagnostic equipment, and etc. I should add that it is NOBODY that I've used, and NOBODY who is doing any tuning for anyone on this board, or O.E.
This is someone who is local to me. The owner of the chip sent me a copy of the .bin file. I was... amazed.

As I said in my PM. I don't know everything, but I'm learning. By necessity, if nothing else.

[Shaun41178(2)]

Ok I didn't know you had it running through an auto tranny. That right there plays a good role.

A 272 cam would help out

I did 149.X with poorly ported heads, and slightly larger then stock cam(not sure of specs yet) and sprint exh with an getrag tranny on a bone stock intake setup.

Your numbers seem about right though.

There are no shops that I know of anymore that tune old crappy obd gm garbage on a dyno. Its all standalone now. I know of no shops that have eprom burners, emulaters, or whatever else one might need to tune our cars or anything obd 1 for that matter.

YOu will have better luck with a aftermarket piggyback system, or a standalone to tune yoru setup in.

I use an safc to tune my fuel curve, and adjust the timing through the distributor, then call Ryan at Sinister Performance for a burn on a chip with the info I provide him. He makes the changes, then I go back to the dyno and do it all over again.

[BigRedDeckSpoiler]

Ok I didn't know you had it running through an auto tranny. That right there plays a good role.

A 272 cam would help out
...

There are no shops that I know of anymore that tune old crappy obd gm garbage on a dyno. Its all standalone now. I know of no shops that have eprom burners, emulaters, or whatever else one might need to tune our cars or anything obd 1 for that matter.

I'm running the 272 now, and ported heads and lower, along with the FOCOA headers. I figure the main restriction now is the 57mm TB.

The tuner that I was talking about had TunerPro, a romulator, a dyno and a wideband at his disposal, and was using all of them. The car that he was "tuning" is a single purpose road racer.
It made good power at WOT, but everything else was crap.
Unless I just missed something, the .bin that I saw had outrageously rich (even to my admittedly newb eyes) fuel tables, and closed loop designed to occur at 150* C !!!
The plugs fouled out to the point of misfire after only three or so track sessions.

Right now, I've got mine really close, according to the BLMs, but there are some driveability issues that were not there when I was running the stock tables with the 19s. (i.e. pig rich.)

[The Dark Side of Will]

Is there a sudden rise in manifold vacuum (drop in pressure) to suggest that the motor is trying to pull more than the intake tract can flow?

Is vacuum relatively constant--suggesting that the heads + cam just can't move the air?

I'm pretty sure it's a runners issue, so it won't show up on the MAP sensor.

Adapting any part of the DOHC manifold will be very difficult.

[The Dark Side of Will]

The tuner that I was talking about had TunerPro, a romulator, a dyno and a wideband at his disposal, and was using all of them. The car that he was "tuning" is a single purpose road racer.
It made good power at WOT, but everything else was crap.
Unless I just missed something, the .bin that I saw had outrageously rich (even to my admittedly newb eyes) fuel tables, and closed loop designed to occur at 150* C !!!
The plugs fouled out to the point of misfire after only three or so track sessions.

If the plugs fowled, it was obviously too rich for the conditions...

What I bet he was trying to do was to force it to run open loop all the time and then adjust open loop accordingly. I have NO idea WHY he was trying to do this unless he was just an ignorant fool...

Engines that see prolonged periods of WOT do need to run VERY rich (like 10.5:1) in order to keep the chambers cool and not hole pistons. The thing is, GM programs AUTOMATICALLY drop the AFR as time at WOT increases... and you can TUNE how much to change the AFR and how long it takes...

So the guy *may* have had a half-assed idea of what the engine needed, but sure as hell didn't know his way around GM computers...

[Shaun41178(2)]

I know gm computers do that now, but do you think the were programmed way back in the 80's to run rich after a certain amount of WOT time? I am not sure about that.

[The Dark Side of Will]

That's not such an esoteric feature... when you're building a car for anyone to drive it and do anything the car can do without breaking, you get to the ability to run WOT until the tank's empty pretty quick...

The $A1 code mask that Ryan uses to run the Northstar has it and that dates from about 1990.

[nfswift]

Ok seeing as discussing the specifics of the build has become more important I guess I'll just lay out the "big idea" so I can refine my concept if that becomes necassary at this point, based on the feedback from more helpful folks around here of course.

Starting from the top down.

I plan to use a dual plenum with single TB style upper manifold, I will be looking into the ideal total volume, port sizing/shaping, and devising a way to place the runners. I will be running at least a 57mm TB, possibly larger, but I don't want to kill velocity and throttle response. With my design I'm at least hoping to do away with the the upper and middle IMs, I'm likely going to massage the LIM ports a bit as well to help it keep up.
I will be staying with stock injectors and I am debating what to do about the EFI and ignition.

When I have the heads matched to the block I'll probably have my shop shave them 0.010" to bump compression, I'm also considering a 5-angle grind but have not budgeted for it. I will likely be buying a decent rocker set with springs to match the new cam. I will also be researching the most effective porting I can do to the heads myself to help overall flow keep pace with the new components. I will be looking into have some headers made here as well.

As for the cam I havn't specifically chosen one yet but am searching for one that pulls the strongest in the mid to upper-mid range. A cam that winds out hard but isn't run ragged to get peak power.

I may be investing in new 0.030" over slugs, it's hard to say yet, but I will at the very least be buying new rings and honing out the cylinders depending on the current shape of them. As long as the rods and crank are still in decent shape they will be reused as well.

Water/oil pumps and the alternator will be replaced according to their condition.

That covers the majority of it..

[Shaun41178(2)]

You are already in over $1k. Better revise your budget. Like I said for what you want, $3k is abetter target.

[nfswift]

Seeing as I'll be welding the intake I'm only paying for the metal here.
A used TB is pretty much chump change as well from any wrecker $30 dollars maybe.

I'm looking at $140 for a cam/lifter set. $150 for a valve grind, $100 pushrods and springs. $150 for shaving the heads.

$150 dollars for the hone, roughly 200 for pistons should I need them, and another $130 for rings.

$120 dollars for a complete bearing swap. $50 dollars for a neutrally balanced fly.

I should be looking at 900-1200 depending how carefully I purchase parts, and thats being generous for some parts, I may come under, or have excess that goes to an unexpected part.

The only thing I am overlooking here is headers.

I don't see where the other 2,000 dollars is going to go aside from a turbo...

[The Dark Side of Will]

I will be running at least a 57mm TB, possibly larger, but I don't want to kill velocity and throttle response.

You don't have to worry about that with a 57 mm TB.
You won't "kill" throttle response... if you go too big on the throttle, you may just make it hard to come off idle smoothly. If that happens, you can change the throttle cam to help. My dad has a 75 Jaguar XJ-6 with a TPI 400 SBC (Torquezor!!) in it. With the TPI throttle cam it was difficult to pull away from a stoplight without chirping the tires. A simple swap to an LT1 throttle cam cured the problem.

I may be investing in new 0.030" over slugs, it's hard to say yet, but I will at the very least be buying new rings and honing out the cylinders depending on the current shape of them. As long as the rods and crank are still in decent shape they will be reused as well.

Water/oil pumps and the alternator will be replaced according to their condition.

That's a really poor way to deal with one of the most important aspects of your engine build--ring seal. Ring seal = power. Think about it... You block left the factory with a nice tight production cast piston bore clearance. As the miles ticked away, the bores have gotten wallowed out oblong. If you hone them round, they're going to be bigger still... If you drop stock pistons back into those bores, your bore clearance is going to be way out of spec and you'll get a lot of piston rock and piss poor ring seal. Build it right. You sound like you want to do the job the way it ought to be done...

Either buy the aftermarket hypereutectic pistons in a standard overbore and have the shop bore the block to match, or have the shop bore the block whatever it takes to clean it up and order custom forged pistons to match.

Also consider getting coatings on your pistons and using total seal rings. That's a handful of ponies you don't have to find in the airflow components you've used many words to describe.

Budget for a high volume oil pump (and install the stock regulator spring).

[nfswift]

You don't have to worry about that with a 57 mm TB.
You won't "kill" throttle response... if you go too big on the throttle, you may just make it hard to come off idle smoothly. If that happens, you can change the throttle cam to help. My dad has a 75 Jaguar XJ-6 with a TPI 400 SBC (Torquezor!!) in it. With the TPI throttle cam it was difficult to pull away from a stoplight without chirping the tires. A simple swap to an LT1 throttle cam cured the problem.

Like I said, i just want the TB to be able to keep up, I may or may not upgrade here, perhaps I'll buy a larger one and do some A/B testing and see which one gives me better results.

That's a really poor way to deal with one of the most important aspects of your engine build--ring seal. Ring seal = power. Think about it... You block left the factory with a nice tight production cast piston bore clearance. As the miles ticked away, the bores have gotten wallowed out oblong. If you hone them round, they're going to be bigger still... If you drop stock pistons back into those bores, your bore clearance is going to be way out of spec and you'll get a lot of piston rock and piss poor ring seal. Build it right. You sound like you want to do the job the way it ought to be done...

Either buy the aftermarket hypereutectic pistons in a standard overbore and have the shop bore the block to match, or have the shop bore the block whatever it takes to clean it up and order custom forged pistons to match.

Also consider getting coatings on your pistons and using total seal rings. That's a handful of ponies you don't have to find in the airflow components you've used many words to describe.

Budget for a high volume oil pump (and install the stock regulator spring).

As for your argument here, there is no argument, the bore would have to be ideally (see UNUSUALLY) tight for me NOT to go 0.030" over and only time will tell if this is necassary. What kind of reputation does Speed-Pro have? Summit offers their pistons pretty cheap, I just wanna be sure they aren't total shit. As for coatings, that's a tricky one, I'm not exactly sold on how much benefit I'll see from my set-up, which in the big picture is a pretty mild build? When I mentioned gapless rings my machinist seemed pretty un-sold on them and remarked that they were usually only required on alcohol and extreme builds, this machine shop builds mainly sprint car blocks and has their own dyno stand so I took his advice as pretty honest /shrug, I refuse to rule anything out though, because I would definitely love to see miracles from this 3.4, and if coatings and rings will really tip the scales I'd look into it.

[The Dark Side of Will]

If the stock rating of an iron head 3.4 is 165 HP, you have to come up with 25 HP outside the engine to meet your 190 HP goal, if you start with a good condition stock longblock.

If you start with a 170 or 175 HP longblock, then you don't have to find as much outside the engine. If you can find 25 HP outside the engine (I think you can), then you end up with 195-200 HP instead of 190.

You can play with and tune the intake and exhaust tracts fairly easily, but changing things inside the engine is much more difficult. Build the engine as much as you reasonably can and you won't regret it later. You may, however, regret NOT building it later if you elect not to.

Use 3.4 TDC/DOHC pistons to increase compression...

[nfswift]

I'm not exactly sure where to find TDC pistons, I heard they are a bitch to source, and between shaving the heads and stuff wouldn't I be raising my comp too much? I'm not sure what ratio it begins to cause valve clearance issues at, but I want a ratio that will still play nicely with the cam, and run pump gas, I'd prefer not to run premium unless I'm actually running a turbo or something that needs it.

I don't know what the specific differences were between the 160-175HP longblocks, seeing as I am practically doing a ground up rebuild it'd probably be worth making sure I have the same changes integrated into my block that are associated with the high HP block. Who knows, the parts I'm using might be better than whatever made the difference to begin with.

[Shaun41178(2)]

I have 30 over pistons here. But they are for a 3.1 bore I think. Too bad I would have sold them cheap.

160 hp blocks have iron heads. 175 hp blocks are the gen 3 aluminum head engines.

[nfswift]

160 hp blocks have iron heads. 175 hp blocks are the gen 3 aluminum head engines.

Ya that is what I gathered from the 60*V6 website.

And ya, too bad, I'll probably be buying some Speed-Pro hypers from summit. There is a variance of price between them for some reason, it's not related to diameter, dish, dome or anything I can see in the product description, and I wanna find out why one slug is 28.99 and the other is 36.99.

Plus I still need to decide on the right cam.

This build is pricing out may just North of $1000 but not by much, and 190 HP doesn't seem impossible...

[Shaun41178(2)]

you going for 190 whp or 190 crank hp? because 190 crank is like 160 whp. Thats easy to do. 190 whp is a different ballgame though.

[nfswift]

you going for 190 whp or 190 crank hp? because 190 crank is like 160 whp. Thats easy to do. 190 whp is a different ballgame though.

Well seeing as 160WHP is still another 45 odd WHP over the average 2.8 on a dyno that would be respectable. DOHCs put down 185WHP on average.

I'd be very very satisfied if I could break 200 crank.

200WHP sounds a bit extreme, but wasn't oreif over on OE running over 230WHP... it can be done, and its a tempting concept.

[nfswift]

BTW, just curious Shaun, but what makes you estimate 15% loss from the fly/crank to the wheels?

I havn't dealt with dynos at all yet, but I understand the concept of drive train loss (DUR) and the other parastic effects that kill HP, but 15% sounds really inefficient for a FWD type drivetrain (well it IS FWD... in the back).

To my understanding FWDs lost less to the wheels than RWD equivelents, and way less than AWD??