Turbo 325

[bangn]

Started today, its been a busy week. Cam is broken in and first oil change out was very clean exception to the slight shimmer under light, no nasty chunks in the filter. Its very peppy and surprisingly quiet on the valvetrain front. I thought the steel rockers would of been louder but its the quietest its ever been. Very smooth too.

Only issue I have is home sensor not staying in full sync and began to drop out after about 10 minutes, so Il need to reposition the cam tone wheel as its too close to the crank sensor event.

[bangn]

So car is getting a run in and tune on the dyno in a couple of weeks. Will only be on gate pressure whilst its got running in oil in it. Once ive put some road hours to break the engine in a bit further I will take it back for a power tune I would say Early Feb.

Sync issue so far seems to be resolved with the tone wheel reposition so fingers crossed it stays that way, hard to confirm much when I cant run it for a long period.

Ive decided to re-do the oil filter relocation setup as I would like to incorporate an engine oil cooler. I found with the current setup the exhaust manifold is pretty close to the in/out fittings on the Derale relocation block and feel I am taking on some excess engine oil temps due to this. The Derale block is chunky and then with an added NPT fitting plus 90 degree fitting it makes the stack height excessive. So may as well do what I can now to add some more engine protection. I'm sure on a power run the EOC will be beneficial to the tuner in maintaining good oil pressure. NPT fittings to me also just look yuck with excess thread hanging out.


So getting rid of the Derale gear and going with improved racing, must say I was really impressed with their website and ability to customize their products to your application, they run ORB fittings which is great and should help free up some room

Oil filter housing with thermostat. I have picked the 215f version as the vehicle is a street car.


Inline block so I can relocate the oil pressure sensor as well as incorporate an oil temp sensor


KOYO 19 row cooler, the SETRAB cooler nearly won selection but KOYO run ORB fittings so no brainer there.

[bangn]

The quality of improved racings products are exceptional, highly recommended!

[bangn]

40 degree days have backed off a bit so had a chance to do this today. Took 6 hours which included masking everything up, vacuming as I went to prevent galling and marking the bores. Got the protrusion and spacing bang on which I'm very happy with seeing it was my first go at oringing a block. Def not a quick job in situ. Best thing is the oring grooves fell exactly where the marks were in the block left from the back of the cutring so that worked out well.

Hopefully does a better job at sealing than the cut ring gasket that shat itself after an hours use.

[bangn]

so small update, 2024 is proving to be quite a challenging year. So on top of the cut-ring gasket failure I've experienced on this engine, its also been found the head had developed a crack in it from said gasket and was not picked up by my machine shops usual testing before I bolted it down the second time round. It was cold pressure checked but probably should of been hot pressure checked its been found as it had a crack an inch long inline with the head bolt supports on the intake side on cylinder 5. The shop wanted a challenge and offered to fix it for me for free, however once they heated it up it cracked from head bolt to head bolt. I've never seen something so cavernous. Worth a shot I guess if I could of obtained another year of use from it whilst I source a replacement but that's life for you. Downside is that its taken two months get the answer I needed from the shop but nothing seems to happen fast in the machining world anymore.

So I've ordered a new AMC head, well aware the ports suck but there is a machinist in Adelaide called Knight engines who I've believe have the ability to get them to flow a bit over 200cfm so hopefully I can see that through. Hopefully can get on top of this car in the next couple months.

Other news the other E30 I have which is a 323 ive picked up a VCT SR20 combo for it, but really bad timing with this head. I want to start but I refuse to start until this car is back together.

[zwill23]

Man that's a tough break.

I keep hearing more and more stories of the 885 heads cracking, seems at this point it's luck of the draw when having one built. Going with a new AMC head is a smart decision I say, I imagine the reduced flow won't matter as much in a forced induction application.

[Panici]

I imagine the reduced flow won't matter as much in a forced induction application.

Of course an engine that flows better (and makes more power) N/A will also flow better when boosted, but when you can dynamically adjust the amount of air via boost pressure it isn't a big deal.


I've read that new engines are being designed more for knock resistance than flow (shallower valve angles among other things?).

The idea being that you can just cram more boost in there on a knock-resistant engine to make the same power, and run a lower octane fuel in the process.

[bangn]

been a bit so thought id update.

Car is driving again and has been going for a couple of months without fault. Trying not to jinx it however I am very happy so far. I've completed 320kms (200miles) with the reduced power run-in tune and all the vitals are really consistent. I performed a check over the valve train couple days ago and only really found a handful of adjusters to be out .05mm. The AMC head I unfortunately was not able to get cnc matched as the business I was going to use seems to have shut down. TBH I am kind of glad that I didn't because I learnt that not all ports are parallel on the AMC head and I feel there would probably be enough core shift there to break through a wall.

So I took a different approach. I spent nearly 40 hours on the port cleanup myself and spent probably longer researching port designs. The design is very close to how my last head ports were however I feel this head promotes intake velocity more due to a narrowing just before the valve stem. The 885 head is a fairly straight port to the valve seat however the AMC funnels. The inserts also sit much lower in this head. The throats didn't even need to be touched as they were exactly the same size as my last head AFTER the valve job. The headshop that tried to repair my last head didn't even charge me to put in the larger valves and multiangle seat job. Absolute legend he was!

I've also noticed with the AMC head that the intake is MUCH cooler, the 885 head seems to use the intake almost like a heatsink and was always hot after a drive. Now its as cool as a cucumber after an hour and a half of driving.

the 2.9 is a very different M20 to drive, there is loads of torque and you forget it even has a turbo its that responsive, essentially no turbo lag. I am able to overtake cars in 5th gear at 100kmhr without even having to pull back a gear to get the motor going. Torque is just everywhere and its still fast doing a 3rd gear pull with a lowered rev limit. Then there is the sound, its much different. Far more angry on gate.

Hopefully by the end of July we should see the proper figures after the final tune but I think its going make me shit myself

[bangn]

Getting closer to being able to provide a dyno sheet but here is where we're at

Previous engine made 350rwhp at 22 odd psi, its now making that at 14psi

Tuner got to 416hp @ 20psi today until it started blowing cooler hoses, the clamps have found their limit so hes going to swap
out the clamps Monday so he can finish off the tune.

He advised the new AMC head is WAY better than the 885 head and that its spooling up the turbo a lot sooner, gains across the board there so i'm stoked with that.

Advised fuel pressure is becoming an issue with the compensation for boost, the pump is plenty big but its sounding like the connector/power feed to the pump is now insufficient

We are now pushing the limit for 98 fuel as timing is now requiring to be pulled at higher boost pressure to compensate. E85 and a larger gate will likely be required on the next loom build.

7k RPM is the limit with this intake its seeming but I expected that.

Mechanically the engine is doing very well and has a lot of power left in it. However now all the power is essentially on tap instead of having to work for it, it may be enough? time will tell.

I have requested a video of the run so il be sure to upload when I have it

[2mAn]

those are some great numbers, Ive been trying to convince my buddy to follow through on turboing his m20

[McGyver]

That's really unexpected for the AMC head to flow better than an 885. Do you think it all comes down to the time you spent porting it?

[bangn]

That's really unexpected for the AMC head to flow better than an 885. Do you think it all comes down to the time you spent porting it?

Yeh I don't think a standard AMC head would of achieved what this did, out of the box they suck!


So car is finally home, here is a teaser below
https://www.youtube.com/watch?v=pTA4eUehUy8 - dyno run on low boost 14psi

For now high boost is turned off until the fueling issue is resolved, as mentioned earlier the wiring to the pump is insufficient so will need to be changed. Also
found the return line is undersized (likely at the tank) as this is creating a pressure spike when coming off high boost and throws the ecu into limp mode. Its just factory sizing but we're now pushing the maximum capacity
with that pump. Going to need a big think on the direction I want to head at this point. Flex fuel is what Id like but its not as easy as changing fuel lines, need a larger pump and the waste
gate will be too small for it (need a 50mm instead of a 40). Likely going to have to modify the factory cradle to accommodate all this as the factory plug connector is also undersized.

As you can see the latest sheet below is where we are at for now, after 400 it was just becoming too unsafe and tuning could not go further. But to compare the second sheet marked in orange is the tune it had on the 885 head on this engine with 7psi of boost
until the engine was properly broken in. The response with the new modified AMC is a lot better, power is near on instant.

Weekend is meant to be sunny so il see If I can squeeze in a video of a pull and the idle, its very spicy even on low boost



Marked in orange - same engine but AMC modded head fitted instead of 885 @ only 7psi - still using 1mm oversize valves and same multiangle job performed with port cleanup

[McGyver]

Do you have any specifics on your porting process?

I've got a refreshed 885 head that is ready for a 2.7i build. It'd be nice to get it flowing as best as possible before assembling the enigne.

[bangn]

Without a flow bench its pretty risky to do anything major so I err on the side of caution there. Id recommend watching as many videos as you can from Headgames and David Vizard as their knowledge is extensive
and will aid you in making decisions on what to touch and not to touch. On the 885 head its especially risky to make changes as you can make them worse than oem however I feel you can remove casting ridges and smooth out transitions carefully without detriment to the port design itself.. AMC head needs a fair bit more cleaning up than the 885 head

ie below - this is an intake port on the AMC head and as you can see the injector relief is more of a wall, its also not even central.
I port matched where the red arrows were as this genuine gasket was exactly the right size as the 885 intake port. Only a small amount of material to remove
Now where the square is took a fair bit of time as the roof was so low the injector couldn't get a good firing line at the valve. I raised this up so the roof was a clean sweep from left to right.
This reflected the design of the oem which was what I was trying to get close to. I then had to make my own injector relief which was very painful to match between each port.

I was fortunate enough to have an 885 head to compare my work to and the most important thing is to make small changes and do those small changes on each port as you go. Don't finish a port and
then start the port next to it from scratch, that's the sure way to have ports different. I also used a dremel on a snake, material removal was slow but very accurate. Die grinders very fast and its very easy
to start chasing your tail trying to fix fkups.




as you can see below here how bad the AMC head can be. Each port is different.


The green circle - throat. Leave it alone as this needs to be a percentage of the valve size, if using larger valves leave the head machinist to size it. Luckily on the AMC head the throat size
was exactly the same as the throat size on the 885 head which was only slightly enlarged by the machinist.
The red lines are areas I would smooth out to the bowl shape but then retexture it to the finish of the port - rough is good, smooth is bad (applies to intake only)


Exhaust side was much easier than the intake as it just needed the cleanup around the bowl area and a casting line from the mold. After this I went around the combustion chamber and took the hard edges out of everything so there is less risk for hot spotting

I still feel where the AMC shines after its been cleaned up is how the port is a bit more tapered towards the valve guide rather than straight on either side from the start of the port through to the valve seat, this should be beneficial to better velocity.

[bangn]

heres an example of an intake port cleaned up on the 885 head I had, nothing serious just took out the ridge lines