304 intake manifold swap.

[immortality]

Working on a manifold swap for my VS II Senator 185i

This all came about when the engine died one day on the way to work. Initial diagnosis was a lack of fuel pressure (couldn't hear the pump running), anyway changed the fuel filter, checked it all over, perfect pressure but still no vroom vroom. Than after more electrical checks it looks like we have no spark.....

Finally pulled finger and stripped the intake off, pulled out the dizzy and module. Intake needed to come off as the intake gaskets were toast

In the mean time I sort off went on a little health kick as I'd been doing it tough since I stuffed my arm/shoulder a few years ago and part of that was getting some exercise including walking to and from work so I decided to leave the Senator parked up because quiet simply, have car will drive...... Then I decided I didn't like my job anymore and started looking for work so needed a working ride but I was pained to put the banana's back on the old girl.

I'd been on the look out for a TP dual plane manifold but nothing popping up here in NZ and couldn't really justify the price of a new one with the cost of shipping/exchange rate etc to NZ and the one day a used Harrop dual plane manifold popped up on Trademe (Thanks VK3800 for the heads up) so it was quickly purchased.

So right now the manifold is just about ready to be bolted onto the car and looks something like this

I'm gonna strip it down and take it to work and give it a good clean in the parts bath to get all the crap/swarf out.

The manifold is from an ex NZV8 touring car, as such it was already drilled to suit rear coolant bleed so I added those in too and has had the runners ported about 6" up the runners to match the heads ( I had the injector bosses machined to suit).


Originally I was going to use the standard fuel injector rails but it looked like there were going to be some clearance issues for the air cleaner (from the throttle body height) so I ended up getting some new Aeroflow rails and things have kind off snowballed from there. It now has a Turbosmart 800 FPR and a few Aeroflow black braided lines as well as an Aeroflow 1375cfm 4bbl TB. Will most likely top it off with a K&N 14x3" Xtreme top air filter.

The plan at this stage is to get it up and running with this intake and then in the near future throw a cam at it, most likely a Kelfords cam item (the same as Delcowizzid used in that Torana) and maybe track down a set of heads that I can give a quick tidy up and skim the crap out of to get the CR up with a stock bottom end, I also have a NOS plate kit to go on it. The long term plan is to fit a T56 with some 4.11 gears in the diff but I may persevere with the auto for a bit if I can find a decent torque converter.

[MAGP]

Watching with interest.

[immortality]

There was also some discussion on another forum about the size of the 4bbl TB for these engines.

To quote Hoopstar from another forum (hope you don't mind),

Funny, I was speaking with Craig from Torque Power about this exact thing just the other day.

During some back to back track testing he did exactly what you’re suggesting and disconnected the secondaries in a 1000cfm TB and found the car ran no slower. His suggestion was to run one of CRD’s 750cfm throttle bodies.

Theoretically a 1375cfm throttle body will support enough air for a 304 turning at over 15,000rpm with 100% VE or a 355 at 13,000+ rpm.

Interestingly a 304 turning at 7,500 rpm and a 355 to 6500 rpm only require around 660cfm (at 100% VE) – around the same as just running the primaries only . If you do the calcs with a more realistic 85% VE of a nicely matched street engine, the 660cfm throttle body will support 8800 rpm (304) & 7500 rpm (355).

Just some food for thought and would certainly be worth some testing..

The plan at this stage is to do some testing with only using the primary pair of butterflies and then possibly with the secondaries opening different amounts depending on manifold vacuum at WOT.

Just doing some quick maths, the stock TB (65mm) has a surface area roughly 3318mm², a 70mm TB is approx 3848mm² (ignoring the butterfly shaft).

Each pair of the 1375cfm TB is 3103mm² so slightly less than the 65mm TB. So testing with the primary only is probably a good start. This TB has the butterflies opening inwards which is supposed to improve air distribution?

I'm planning on running the same cam that Delco put in that Torana which is still running the banana’s manifold and 70mm TB. Delco said that intake was holding that one back as it was starting to pull a vacuum at high RPM WOT.

[immortality]

So this is how it sits this arvo,


The original plan was to have the FPR mounted off the back of the fuel rail but it's going to foul on the trans dip stick tube with the fuel pressure gauge fitted so that is going to require some thinking. I also forgot to drill/tap a hole for the dash temp gauge sender so I've done that this arvo. She's all stripped down for cleaning now.

Once it's on the car I can start working on the wiring loom, I'm going to unwrap it and pull the wiring back for the TPS and IAC, hopefully there will be enough length to not have to cut/extend anything. Looks like the heater hoses will need replacement too as the original moulded hoses aren't going to sit quiet right.

[delcowizzid]

Bend the dipstick tube out the way they are pretty soft just stick a bit of round bar down it and lean on it lol.ide probably go the next cam up maybe but you might want a single plane for best results.will want a converter for both we had a tight 2500 converter could of done with just a little more but did respond good enough that you could stop it from idle into top gear burnouts with ease lol

[immortality]

That's not a bad Idea, I'll sort out the heater hoses first to get em out of the way and then see about the FPR/ filler tube.

I think a 3000rpm converter would be the go, where did you get your's from?

[VK_3800]

Nice.

I wouldn't worry about mucking with the throttle body to begin with unless you have poor range at the pedal (i.e. too much in the first part of the travel and no additional response beyond that). If it is an issue you could look at tweaking the lever ratio so it simply doesn't pull the butterflies completely open.

Kelford make good cams, are you referring to the 170-E? Bear in mind their cam cards quote the lift with 1.6 ratio rockers so it will be a bit more and you will need different springs.

[immortality]

Hi Mate,

Was originally thinking about the Kelfords 170-D (224°/224° 110lsa .480" lift) but Delco thinks I should go with the 170-E (234°/234° 110lsa .520" lift). Was considering some of those Scorpion 1.72 rockers to get some decent valve lift happening.

edit: another option for the FPR might be to get rid of the pressure gauge which is fouling and just mount a 100psi pressure transducer instead to use with the data logger. I have ordered a new sensor just in case I decide to go that way.

[VK_3800]

The D is borderline with standard valve springs anyway (I wouldn't do it - that's 0.495" lift @1.65 ratio) so may as well go E, cost is the same for parts (assuming you go ahead with a high stall converter) and of course you can tune it to suit. Dunno about the rockers, once you go over 0.550" lift you'll likely need to go to double springs which is more expense in parts and machining when the cam will be pretty good as is and right in the sweet spot for a good set of single springs.

Being able to log the fuel pressure would be pretty cool and the gauges on the regs tend to be a bit crap anyway.

[delcowizzid]

I wouldnt be using stock springs on either cam lol we measured the old ones 40lb seat pressure and below well past the useby date.