drnick

dennis, i collected the car yesterday morning after it had been off the road for ages having bits and pieces done. ive had the headers for probably over a year waiting to install them and while that was finaly happening the cams turned up they have been set as per jims specs and the car runs absolutely sweetly, idles just fine but there is this screaming sound that just keeps going right the way through to redline

first impressions from driving are that it revs more freely, absolutely the power is shifted up the range and it keeps pulling with urgency all the way past 6k to the limiter which is at 6900. id predict peak power at 6700 or so. there seems to be a slight drop in tourque at about 4500 but im not sure the flappy is actuating - i have to check what the guys did with the vacume lines and the throttle is not yet opening all the way. one thing i have noticed is that the air fuel gauge reads rich more of the time?? if anything i would have predicted leaner running with the headers. it is definitely making more power, it gets to 140 quicker than before pulling when in double figures with more vigour.

a friend who has GT cams in a GTS drove it and he found that it revved more freely than his engine as well so i wonder how much of this is the headers vs the cams? if i had more patience i could have waited to install the cams - but im far from unhappy with the end result anyway! the exhaust is quieter at idle but definitely louder when the throttle is open. on the motorway cars actively pull over if i am behind and prod the accelerator.

do you guys think the cam timing needs to be ajusted significantly and how much do you think the sharktuner will add?

drnick

jim, i forgot to mention that the car now feels like it wants more air into the engine. in another life i would pull the heads and add 968 intake valves. i think a good set of headers and exhaust sorts one side of the engine after which im understanding why people have such gains from the intake mods, throttle bodies and 968 valves.

Jim Morton

Nick:

From the flow bench work done for my 6.1 liter motor, I would suspect the restriction of the stock intake setup over valve size at 5.0 liters.

I very much want to make new CNC milled tank ends for Dennis' and my cars. The flow testing of the intake manifolds strongly pointed to the end plates as a major issue. From there, the runners become suspect.

$0.02...

BC

I was thinking about replacing the end plates with triangle assemblies with Throttle bodies for each side. Yes, the runners can still be an issue, but the plates being 1/2 inch or less away from the plate problem is now gone.

The other issue, even with boost (or large with boost) that there is a huge difference in the air that gets to each port. Each runner is length set is so different than the opposite that Todd found I think a 20% or more percent change needed in fuel. 20% air flow differences is huge.

It almost seems like scraping the whole thing is a good idea.

drnick

this engine now screams and revs just back through the door after a couple more hours on the road.

Bill Ball

BrendanC: Tom Cloutier mounted spacers and a throttle body on each side of my intake manifold and we got no change in peak HP. This was when I was normally aspirated. There was some improvement in mid-range HP by about 20HP at various points in the RPM curve, so the area under the curve was greater, but over all it wasn't worth the expense and hassle of the two throttles and linkage and other hardware. I believe what Todd observed about the flow differences from one intake runner to the other, and over all the S4 intake is very restrictive [See subsequent post by Jim Morton for more details]. Phil Threshie's intake seemed to add quite a bit of HP, and some more work along that line, perhaps with less expensive materials and methods seems like a real good pursuit.

Glad to hear you are having fun, dr. nick. Now that Dennis has finished seating the new rings, he certainly is too.

drnick

bill, im picturing an intake like phils but in aluminium. this shouldnt be too expensive and if im not mistaken it has just about all of the advantages of an itb setup excepting the instantaneous response?

Jim Morton

As another data point, while flow testing the heads to my 6.1 liter engine project, we flow tested the S4/GT/GTS intake. Here is a rough summary of the results.

With the end plates on as OEM, using either the straightest runner or the most bent, the flow at 25" was around 220-225 CFM. Moving the plates out 1/4 of an inch gained about 5 CFM. Moving the plates out approximely 3/4 of an inch took the manifold up to the high 240's with the best runner at 250 CFM... again at 25inches. Only about 5-ish CFM more was gained with the plate completely gone.

The mainifold runners gained slightly with mild porting, but not as much as hoped for. Using a simulated 3/4 inch spacer for the end plates, re-shaped horns to the runners and mild porting got the best runner to 280CFM and the worst to 265CFM, showing about a 10 percent flow spread for the manifold.

With all the test porting and flow work done on the OEM manifold, I am now looking to making some sort of new setup before proceding further on my 6.1 engine. I say this as my heads flow 340 CFM at .425" of lift. Restricting such nice heads with the OEM manifold would be a huge waste !

Given the results with the OEM manifold, I cannot see moving forward building an engine that gets restricted by the OEM intake to a point where it's a whole lot of money to simply end up frustrated with the result...

In the mean time, I think I can wake up my 5.4 GTS engine with some cams and tuning and have a nice "hot rod" road car until the intake can be designed and fabbed for the 6.1 liter engine build. I suspect the intake project will be a this coming winter time effort.

$0.02

drnick

jim, im following this stuff roughly.. how much do stock heads flow by comparison, is there a discrepancy between what a stock head can achieve and what the stock intake will deliver?

BC

3/4 inch spacers have some issues as sterling states. But it begs the question of making a new intake possibly in the long run being less hassle than getting the thicker spacers to work with the fuel rails.

drnick

i agree with brendan, especialy as the standard intake is an averaging process with the various runner sizes. ive asked before and maybe no one here has looked into this yet but what would the dimensions of the runner for a 5.0 or 5.4 litre engine be - aiming for max bhp at 6400rpm? where can one find this info?

Dennis K

Nick -

Can you give us an update on the specs of your engine? It's a GTS right? And now you have the Elgin 65-6 lobes on S3 cores? What other mods? Which headers, ECU, injectors, etc? Now that a few of us have these cams, it'd be good to compare notes.

Re: intake runners - http://www.team-integra.net/sections...?ArticleID=471 No one seems to agree. I have a couple more books and their sizing calcs don't match any on that webpage.

drnick

dennis, its basicaly a stock 1992 GTS engine with the elgin grind on the S3 cores. it has the devek level two headers which i picked up off the list a while back but only now added, these go into a 3" burns stainless X which then gets necked down into dual 2.5" pipe with custom silencers made localy. ive also added intake spacers, they are not very large and i did take out the slight lip in the intake runners at the block end. the heads are stock GTS and come with some port matching from the factory. i was running a slightly massaged GTS cam set prior to this and i did shark tune the car with significant gains after remapping both the LH and EZK, im still running this chip set. ideally i will go back and see john speak and remap again, as far as i know the injectors are stock and came with the engine. ive booked a dyno slot for two weeks time, i only hope i dont get an antisocial behaviour order or driving ban in the mean time!

Dennis K

Thanks Nick. I know John Gill (in Australia) has installed these cams on a 5.0L motor w/ 968 int. valves. He has already gone through Sharktuning w/ a Tech Edge WBO2 meter. Hopefully he'll chime in w/ his results.

I think I'm already near 1000 miles on the engine. Always finding excuses to drive it, just to listen to that howl.

BC

The size and length of runners is so important to where the power is that the fuel resonance intake design is still vitally important, even more so because we won't be getting any variable lift any time soon on these engines.

But when I took my first S4 intake apart, it was immediatly apparent that this is an issue where I think they liked the form and put function in a back seat.