Which way would you go?

[Reynard38]

My engine builder is proposing 2 options.

1. NA with forged crank, carillo rods, extensive head work, extrude honed manifold, cam, headers, yada yada yada. Basically build the best 2.7 possible for the street/trackday.

2. 2.7 with the crank and rods. lower C/R. Turbo. He is claiming this will.
produce 295 rwhp.

I generally prefer NA motors, especially on the track. More linear power delivery. Plus I like a motor that is very free reving.
However HP and torque are intoxicating. Hell with 295 at the rear wheels the damn thing would outrun my Porsche.

Help! I am sliding down the slippery slope and I can't get up!

Which way would you go and why?

[JGood]

Neither. S52 swap. Stock motor and tons of power. You can also get 240rwhp without too much work, and it will be very reliable. The powerband would be great compared to either of your current choices.

[mrsleeve]

All right with the 2 options listed. Why would you need the forged crank and carillo's In the NA motor when a stock ETA crank and I rods with a custom piston would be way cheaper and the rotating mass way lighter, the I rod's are already forged an a ETA crank will hold anything you can do with no boost or NOX

Option 2 lower the comp ratio and boost it? for only 295whp? Why lower the comp for that that, you are in the neighbor hood of 7-8 psi not a prob on 8.8:1 with a proper tune. If you lower the comp much more than 8.5:1 you will a very sluggish pile of crap off boost.

So If it was me (also what I am building myself) I would combine the the 2 and run the forged crank (although not actualy needed, say most people) the custom rods and pistons and keep the comp ratio to around stock and run a big ass turbo and boost the shit out of it for 400+hp

just my 2 cents

[Reynard38]

Can anyone here reccomend a turbo kit? I do not want to fabricate parts. I would like off-the-shelf and bolt on.

[StereoInstaller1]

I would call CarTech and see what their timeframe is for the "re-release" of their kit. I drove a 325is back in '87 that had their kit...I dunno which stage. I would call the power "seamless" and brutal.

This kit was designed by Corky Bell. He got bought out by his partner or some shit. He now runs BEGI.

If you want a kit and are gonna stick with the M20, at least check it out.

Luke

[e9nine]

Can anyone here reccomend a turbo kit? I do not want to fabricate parts. I would like off-the-shelf and bolt on.

TCD [Turbo Charging Dynamics] has a kit. There's a local guy who can perhaps help you fab something as well - Mike McCoy is his name and he's had a turbo m20 car before. He's real good at this stuff. If you're gonna be at the meet I think he'll be there. If not I could put you in touch with him. I know of at least one turbo m20 in the ATL. One guy had one for a sale a while ago - Home brew that my buddy and I went to test out. Another guy never finished his. One of my bother buddies is looking to get the TCD kit as well in the immediated future. I can put you in touch with him as well.

[BMWSOB]

+1 on the TCD kit. I'm using a lot of there hardware but I do like to fab my own stuff so mine is not exactly an off the shelf kit. I think their stage 2 kit is around 300hp.

Donovan

[Andreas]

Just some food for thought : I've seen turbo M20s at the racetrack on quite a few occassions and most of the time they do 4 or 5 laps and then limp back into the pits because everything is overheating. One track day saw about six 2.7 M20 Turbo cars and only two made it to the end and one of those had to cool down his engine / intercooler with a water hose after every session.

A well built NA M20 will probably give you more reliable fun at the track and depending on how much comfort you sacrifice for daily driving, you can get very close to a relatively serious M20 Turbo car.

[Reynard38]

Just some food for thought : I've seen turbo M20s at the racetrack on quite a few occassions and most of the time they do 4 or 5 laps and then limp back into the pits because everything is overheating. One track day saw about six 2.7 M20 Turbo cars and only two made it to the end and one of those had to cool down his engine / intercooler with a water hose after every session.

A well built NA M20 will probably give you more reliable fun at the track and depending on how much comfort you sacrifice for daily driving, you can get very close to a relatively serious M20 Turbo car.

If I go the Turbo route I am going to be conservative with the boost. 0.5 bar or so with fairly stock compression. I will also upgrade the cooling system and run an intercooler.
With that C/R I won't be giving up the bottom end, and I should still be able to get close to 300HP.
I can use a small turbo and have very little lag with this setup.
Last thing I want to do is build a hand grenade!

I am building this car for DD and trackdays, not the 1/4 mile (400 metre if that applies in your case!)

[Andreas]

Even though we use meters in SA, when we talk drag racing, we mostly use the term "1/4 mile".

AFAIK, if you choose a small exhaust housing for your turbo, you might experience heat problems because the small housing cannot cope with the large volume of gas.

I had a turbo on mine once and after a few drag races at night the engine started cutting out. When I opened the bonnet, I could see the turbo shaft through the glowing exhaust housing. After everything cooled down, the car drove normally again. FYI : 2.7 M20 with Mitsubishi TD06 turbo.

Track sessions are quite long compared to drag races, so heat is a real issue.

[Reynard38]

Even though we use meters in SA, when we talk drag racing, we mostly use the term "1/4 mile".

AFAIK, if you choose a small exhaust housing for your turbo, you might experience heat problems because the small housing cannot cope with the large volume of gas.

I had a turbo on mine once and after a few drag races at night the engine started cutting out. When I opened the bonnet, I could see the turbo shaft through the glowing exhaust housing. After everything cooled down, the car drove normally again. FYI : 2.7 M20 with Mitsubishi TD06 turbo.

Track sessions are quite long compared to drag races, so heat is a real issue.

Thanks for the input. I like what you said re: the small housing.
My engine builder is from SA (as are my nextdoor neighbors and the guy I buy my tires from). I will run this by him. Like I said I don't want to build a grenade, but I would like @ 300hp. He works on my Porsche. He also worked for BMW in SA and raced E30's.

[Reynard38]

Just some food for thought : I've seen turbo M20s at the racetrack on quite a few occassions and most of the time they do 4 or 5 laps and then limp back into the pits because everything is overheating. One track day saw about six 2.7 M20 Turbo cars and only two made it to the end and one of those had to cool down his engine / intercooler with a water hose after every session.

A well built NA M20 will probably give you more reliable fun at the track and depending on how much comfort you sacrifice for daily driving, you can get very close to a relatively serious M20 Turbo car.

How much HP and torque are the normally aspirated 2.7's putting out in SA? The problem I run into here is to make real HP I need rpm. To breathe at those speeds I need to use a radical cam. With such a cam the car won't pass emmisions and it will be a bitch to drive in traffic.

[Reynard38]

Calling Mike McCoy

TCD [Turbo Charging Dynamics] has a kit. There's a local guy who can perhaps help you fab something as well - Mike McCoy is his name and he's had a turbo m20 car before. He's real good at this stuff. If you're gonna be at the meet I think he'll be there. If not I could put you in touch with him. I know of at least one turbo m20 in the ATL. One guy had one for a sale a while ago - Home brew that my buddy and I went to test out. Another guy never finished his. One of my bother buddies is looking to get the TCD kit as well in the immediated future. I can put you in touch with him as well.

I'd like to get in touch with Mike and take a look at his setup.

[ColdAccord]

I'm doing a built m20 stroker, but that's only because I wanted to keep my numbers matching (rare wagon). if that didn't matter, i'd go s52

[matt]

Turbo it, no question.

If you're not worried about keeping the stock motor, do a DOHC swap then turbo that.

Like e9nine said, Mike McCoy is the man to talk to in Atlanta about turbos. My car is at his shop right now.