7mge+T Project

[MPR]

I bought the car NA back in November of last year, fixed the BHG and it's running excellent. Said I was going to leave it stock and not boost it. Yeah that lasted a few months...lol.

Been doing a lot of research and reading on here and other sites with regards to doing NA-T conversions. I just wanted to list my project goals and plans here to get some extra input and see if there is anything I have overlooked.

The plan: Basically to run a stock GTE setup on a ge motor. Engine currently runs strong, compression is good and dead even on all 6 cylinders. Exceptions being it will be run on a megasquirt 2 standalone with innovate MTX-L wide band O2. MS has a built in MAP sensor, so away with the stupid AFM. Also planning to run 3" down pipe and exhaust. Stock CT26 turbo with ported wastegate to help prevent boost creep. HG was replaced with an oem style and stock head studs re-torqued to 75-80ft-lbs, so I'm planning to run the stock CT26 wastegate boost setting (6-9psi or so) and no more. No boost controller. Rev limiter will be set at 6000 to help save the bottom end from over revving (plus no need to rev any higher if it's not making any more power up there and the turbo is just blowing hot air...lol). Also plan on running a better, aftermarket FMIC. The following is a list of necessities (what I could think of so far):

Required GTE Parts:

-Turbo (CT26)
-Turbo stays (brackets)
-Turbo manifold
-Down pipe (aftermarket 3”?)
-Turbo oil lines
-Turbo coolant lines
-Oil filter mount
-Oil cooler and lines
-Oil dip-stick
-Intake/charge piping
-FMIC (aftermarket?)
-Fuel injectors
-Spark plugs
-
-

Required Aftermarket Parts:

-FMIC
-BOV (Bosch synchronic)
-Down pipe/exhaust system (3&#8221?
-Boost gauge
-
-

Other Requirements:

-Complete/install MS/extra wiring
-Install wide band O2
-Mount gauges
-Testing/tuning
-
-

Anything else I haven't thought of? Any other suggestions/thoughts?

It is my daily driver, so the idea is to use as many oem bolt-on components as possible and keep it reliable. This isn't a dyno-queen power-house build. What ever it makes after tuning is what ever it will make. I have no power goal and it will probably never be dyno-tuned. We never dyno tuned our turbo-converted 4agze MK1 MR2 race car and it made gobbs of reliable power from 3000 all the way to the limiter at 7500, so I'm not too concerned with that. I'm all about useable power rather than peak power.

Thanks,

Mike.

 

[MPR]

I take it from the lack of responses that I have all or most of my bases covered...

I did have one question though. In regards to the coolant lines to/from the turbo. I plan on running the dizzy to keep things simple and avoid unnecessary wiring. However, I noticed the coolant lines to/from the turbo run right by where the dizzy is located (mainly the upper line). I have not been able to find a good picture of that area of a 7mgte to see exactly how the lines are run and if they will interfere with the dizzy or not. If someone has a pic of that location on their stock gte, would you be able to post it up so I can see it? Has anyone else run an NA-T and kept the dizzy? I assume I can always run a flex line around the dizzy if the oem line interferes...

 

[MPR]

Never mind. I figured it out.

 

[7mgtextatic]

Hey how are things going? I was thinking of swapping a built na into my turbo car and have no idea what I'm getting into. Any feedback would help a ton. Pm text or call 602471793Five. Thanks.

 

[Supracentral]

Anything else I haven't thought of? Any other suggestions/thoughts?

Have you considered the stock compression ratio on a 7M-GTE is 8.4:1 and the 7M-GE is 9.2:1? In most NA-T applications I've done, we've always used a 3mm MHG to drop the compression ratio down.

Also, the cam profile on the GE motor isn't really the best one for turbo use.

It is my daily driver, so the idea is to use as many oem bolt-on components as possible and keep it reliable. This isn't a dyno-queen power-house build. What ever it makes after tuning is what ever it will make. I have no power goal and it will probably never be dyno-tuned. We never dyno tuned our turbo-converted 4agze MK1 MR2 race car and it made gobbs of reliable power from 3000 all the way to the limiter at 7500, so I'm not too concerned with that. I'm all about useable power rather than peak power.

Why not do a complete GTE swap? It wouldn't cost you much and the extra cost would easily offset the extra work and unknowns.

 

[MPR]

I'm aware of the compression but it does not bother me as I want to keep the off-boost drive-ability of the GE. I'm also not afraid of running a higher compression engine with boost. It just requires more careful tuning for obvious reasons. This is not going to be a crazy high hp build. Probably somewhere around 220-240whp. Pretty much like a healthy stock GTE with a few enhancements and full tune.

Don't have a ton of money, but I do have the knowledge and experience to do this reliably on a budget. I've worked on quite a few 'interesting' projects in the past so I'm confident in taking care of any unknowns that may come along. I might consider adjustable cam gears to reduce the overlap in the timing to make it more boost-friendly.

I do respect your suggestions and perhaps down the road when I have more money and want more power, I'll probably do a GTE swap and go for some bigger numbers.

One other question I just thought of with regards to the differences between the GE and GTE engines; Is the only difference (internally) the pistons, cams and oil squirters?

 

[Supracentral]

One other question I just thought of with regards to the differences between the GE and GTE engines; Is the only difference (internally) the pistons, cams and oil squirters?

Differences:

• Different pistons. (8.4:1-turbo vs. 9.2:1 for the N/A)
• Different intake cam (Turbo cam has .0074 more lift)
• No oil squirters (oil galley not drilled & tapped for them)
• Turbo oiling system missing.
• Turbo coolant system missing.
• Turbo has 2 knock sensors (NA has one, but there's usually a spot on the block for the 2nd one)

Otherwise 100% identical.

 

[MPR]

Differences:

• Different pistons. (8.4:1-turbo vs. 9.2:1 for the N/A)
• Different intake cam (Turbo cam has .0074 more lift)
• No oil squirters (oil galley not drilled & tapped for them)
• Turbo oiling system missing.
• Turbo coolant system missing.
• Turbo has 2 knock sensors (NA has one, but there's usually a spot on the block for the 2nd one)

Otherwise 100% identical.

The turbo intake cam has more lift? I would have expected the NA cam to have more lift. So the exhaust cams are identical as well? Interesting. Is the duration the same as well? I would expect less duration on the turbo cams as well as less overlap in the timing.

 

[Supracentral]

The turbo intake cam has more lift? I would have expected the NA cam to have more lift. So the exhaust cams are identical as well? Interesting. Is the duration the same as well? I would expect less duration on the turbo cams as well as less overlap in the timing.

Exhaust cams on both engines are identical. Turbo cams have more lift and about 10 degrees more duration (opens earlier) on the intake. Running a GE intake cam in a GTE produces a slight increase in low end torque and loses horsepower up top.

Here are the actual profiles as measured (ignore the dark burgundy line, that's a BC aftermarket exhaust cam):

 

[Backlash2032]

Here's what I believe. With only 91-92 octane gas, you won't get much better than 350 horsepower with N/A compression. However, if you have the means to run E85, then you can push past 400 with ease...

I was going to run N/A-T, but then I was given the option of turbo pistons, and decided with the lack of e85 I would just be worried about detonation way too much, and didn't feel like I could meet my power goals, so I decided to go with the turbo pistons. If there were more e85 pumps in my area (closest one is ~20 miles away) then there would be no contest. N/A-T all the way.

 

[Supracentral]

It's simple math. All you really care about is the final compression ratio...

A simple (slightly inaccurate) formula for final compression ratio (FCR) at sea level is (Boost / 14.7) + 1) x CR

For example, if you can run 10 psi on 8.5:1 pistons safely on your fuel, your final compression ratio is 14.28:1

So if you run 8 psi on 9.2:1 pistons, you'll yield (nearly) the same final compression ratio (14.21:1) and it should (theoretically) be safe on the same fuel.

It's not exactly like the fuel cares where the compression comes from. If you run the numbers above and you think 8 psi is safe, start with 6 psi and work your way up to 8 psi, monitoring carefully for signs of detonation, etc.

 

[MPR]

Exactly. And I'm not looking for huge power anyways, so it should be fine with the GE internals.

Thanks for sharing the info on the cam profiles! My background is in mechanical engineering and I'm a huge nerd when it comes to this type of stuff... lol

 

[NCMK3]

Good Luck with your NA-T build, in the process of gathering parts for my 89 GE, trying to find a 89+ turbo harness is a pain in the A$$

 

[MPR]

Just go MS and don't worry about having to swap out the ecu/harness and junk.