2.4T -> Megasquirt + turbo

Zendalar · 12-08-2003, 01:17 PM

Currently I am building a megasquirt fuel injection for my 2.4, and i was wondering if any problems arose if i added a turbo.

It has low compression (7.5), and MS would be able to map the fuel curve just fine. I will be using 2.7 liter CIS intake manifolds.

Boost propably 0.6-1.0 bars

Would it work?

1fastredsc · 12-08-2003, 01:42 PM

Well, since the 2.4 (i think) have the mag cases, i'd be carefull with that much boost and do something about oil cooling as well.

beepbeep · 12-08-2003, 01:53 PM

Well, your eventual problems probably won't be MS-related but connected with inherent weakneses of 2.4 motors...whatever they are :-)

I don't know much about them but as 1fast mentioned, i don't think your mag case will like all that extra pressure trying to rip the studs out. I heard it had problems even without turbocharging...

Cool project, nevertheless...

Tim Walsh · Tim Walsh's Garage

The 2.4 has MOST of the updates that the later engines have. Has this engine been rebuilt? If it has been the I'd hope it would have the oil bypass mod, Case squirters and inserts of some sort at the minimum.

Is your case a 3R/4r case? My 72 case was. If I did this I would want a CHT guage at least since you do have Iron cylinders and they don't disipate heat as well as Al.

Except for the case and the cylinders it would be a great engine to turbo. Or at least I would think it would be. It's got flat top pistons, low compression and mild camshafts that don't have much fuel refersion.

Turbos put lots of stress especially when it comes to heat and on your bottom end.

Zendalar · 12-08-2003, 11:02 PM

Well, they heat up allright..But since the cylinders are cast iron, one would not have the stud pulling problem as in 2.7 liter.

Also since the compression is low, the 1 bar extra pressure won't stress much because these engines have been made to 2.7 (??) Horsepower is horsepower, wherever it comes from ??

I am looking for 200-230 horsepower with the turbo. Already bought the turbo for 50$

Wayne 962 · Wayne 962's Garage

Sure, it'll work - for a while.

The Megasquirt and the turbo is the ultimate way to go for cheap HP. There is no other way to do the Turbo / SC unless you have some type of fuel mangement. The trouble is, the MegaSquirt doesn't have integrated ignition management (I don't think, does it have GPOs for a knock sensor) so it can't retard the timing, which will prevent detonation.

-Wayne

Zendalar · 12-08-2003, 11:18 PM

I was thinking of this too. One could retard the ignition a little, and possibly limit it mechanically. Also, the compression would be still quite low (8.5).

Zendalar · 12-08-2003, 11:20 PM

Oh yeah, and then there are these gadgets on the market that retard ignition the way u want on certain RPMs. And they are pretty cheapo too.

beepbeep · 05:02 AM

Quote:

Originally posted by Zendalar
Well, they heat up allright..But since the cylinders are cast iron, one would not have the stud pulling problem as in 2.7 liter.

My understanding is that studs are pulling out of the case, so it doesn't matter which material cylinders are made of.

Quote:

Also since the compression is low, the 1 bar extra pressure won't stress much because these engines have been made to 2.7 (??) Horsepower is horsepower, wherever it comes from ??

You are wrong. Lowered C/R is only there to compensate for boost...so dynamic C/R will indeed go up as soon as you start boosting. Static C/R on N/A engines is usually decided pretty conservativly, but it's dynamic equivalent on turbocharged engine can reach up to 14:1. So what you end up when boosting is bigger air/fuel mixture inside your cylinder. When ignited, this mixture will force piston down with greater force than it's N/A equivalent (hence greater power) but will also exert greater force in other direction, trying to pull the heads out of the case.

So yes...horsepower is horsepower, and it comes from greater combustion pressure in your cylinders, and that same extra pressure will try to lift your heads with greater force.

I'm not saying that it won't work...it probably will. I don't know anything about how strong 2.4T engine is, there are more knowledgable people here, but what i'm saying is that you should consider raised strain on your studs and possibly do something about in case experts here tell you that they are weak.

Quote:

I am looking for 200-230 horsepower with the turbo. Already bought the turbo for 50$

200hp shouldn't be too hard...what turbo did you buy? My guess is that you bought used Garrett T3 off a old SAAB or Volvo.

They were usually fitted to 2.3L engines and will work fine with your 2.4L engine.

I wish you good luch with project. I really like budget project like this, at least just to prove it can be done (i just got flamed for propozing EFI to one of CIS "good old boys" on 911 Tech Forum

)

P.S.
You could always run with hard-coded ignition...with other words, no advance. ROW 930 had no "boost-related ignition retard", just vacuum-advance to help emissions at low revs...

Your car being so old, it's probably not emission-strained at all (at least that's the law in Sweden, and you Finns shouldn't be much different

)

Zendalar · 04:51 AM

Yea, thats the same here in Finland

The stud pulling problem is related to the fact that studs and cylinders are made of different material -> causes studs to pull from the case. In 2.4 liter they are both made of "steel".

I was also told from one source that one person had modified 2.4 liter T engine to give 220 horsies, without turbo. Displacement was near 2.6 liter (cylinders drilled to near maximum, 86 or 87 mm). He made it as his graduation work from some school.

ah, yea, the turbo is from 2.8 liter Nissan Patrol (diesel)

beepbeep · 12-09-2003, 05:04 AM

Diesel turbos are usually made for lower EGT and usually have smaller internal wastegates, so you might need to fit external wastegate in case you expirience runaway boost at higher revs.

Zendalar · 12-09-2003, 05:06 AM

Yea, well, T does not rev that much

But i already have my eyes on one wastegate my friend has.

1fastredsc · 12-09-2003, 06:02 AM

They also pull because the magnesium is weaker with heat cycles than aluminum. My sc has the aluminum case, aluminum cylinders, and the top row of studs were steel. So by your logic the top row should've pulled. Also, while the cast iron will match your steel studs, iron and steel don't disapate heat worth a crap and turbo charging is going to heat up your pistons more than they do now. As a minimum, i'd keep a very close eye on your oil temps. As far as 200hp, watch the ignition and supply the correct fuel, 12 psi could probably get you there easily, maybe less if you have a good matched turbo.

Zendalar · 12-09-2003, 10:33 PM

Certain models are more prone to pull/break headstuds than others. But I will propably install additional oil cooler.

Wayne 962 · Wayne 962's Garage

Don't expect it to last too long (10-20K)...

-Wayne

beepbeep · 12-10-2003, 03:51 AM

I don't know much about studs but my understanding of problem is that studs on older motors usually pull out of the case, so cylinder material is of secondary importance. Your case is made of magnesium, which is softer than aluminium, so it shouldn't last too long when you subject it to added stress of turbocharging.

Zendalar · 12-10-2003, 05:13 AM

Which part will give up first? The studs...oor?

1fastredsc · 12-10-2003, 05:19 AM

Now that i think about it, wasn't it quoted in bruce anderson's book somewhere about the mag cases not handling over 300 hp reliably? Anyhow, the reason why 2.7's pull and 2.4's don't are because they are subjected to added stress, being larger in displacement and running at hot temps. You may get away with keeping an eye on the temp, but if i were you i'd feel uncomfortable with the fact that your going to positively charge your cylinder with extra pressure and when they ignite, even more pressure. At 7 to 1, 1 bar of boost will put you somewhere around 11 or 12 to 1 of compression under boost plus with heads that are much hotter than usual. All i can say is good luck with it, that's a lot of boost.

TerryBPP · 12-10-2003, 10:15 AM

I think if you used 2 Mocal coolers it would "probably" keep the temp low.

rudy · rudy's Garage

I am planning on installing a T3 on my 2.4T motor. The only exception is I am going to blow through the webbers. From what I have read webbers are some of the best carbs to do this with. My motor is as stock as can be minus the webbers. I know some say it won't work and the motor won't last, but I really don't care. People say nitrous is hard on motors but I have never had any problems with it either. I figure if it blows up I will just build another one and do it to it too. There are many parts availabe to do this and it is a common thing on other motors.
Basically have a boost sensative fuel pressure regulator, MSD with boost retard, and pressureize the float bowls so the carbs still function. Install a rich/lean guage to determine jet size. To me a motor is a motor. If they put turbo's on old VW engines I'd think a porsche motor could handle it. I guess we will see what happens.