Engine Build 2.1L (Brutnus)

[brutnus]

Originally Posted by Spenk

You will need a custom, low-boost break-in map created for your mods. Trying to run the stock map would destroy the build in short order. With a modded block, you'll NEVER be going back to the crap stock tune.

Break-in oil and changes at mileage-specific intervals are also essential. Keep that sucker clean for the break in and you'll get great results from the final tune.

So first crank on the new engine is the stock ecu ok for handling this? Custom low boost break in map, outside of the boost is there anything else that needs to be changed? if not i can baby the car around for the first 300 miles.

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[Spenk]

Originally Posted by brutnus

So first crank on the new engine is the stock ecu ok for handling this? Custom low boost break in map, outside of the boost is there anything else that needs to be changed? if not i can baby the car around for the first 300 miles.

No, as in not. The stock tune is now as useless to you as a screen door on a submarine.

Your stock map requires a stock car for proper operation. What you will have is a long, looong way from that.

You need a tuner to help you with A) initial fire-up map, B) low-boost break-in map, C)final tune.

The break-in oil will need to changed after the initial start-up, then at least once again before the final tune.

[MartinSTi05]

Originally Posted by mowgli29

That's what I was thinking....but I'm wondering if the CR bump would really be THAT bad (assuming the pistons wouldn't just smack the heads).

I mean, it'd certainly help off-boost power/drivability... though it would limit my overall power potential. I have to wonder how much it'd limit power potential though... might it be worth the tradeoff? Sorry to clog up the thread with my questions, lol.

Just to clear up the piston misconceptions. A piston for a 2.1L stroker MUST have a ~2mm lower compression height. Otherwise the piston will come proud of the deck and hit the heads. going to 79MM from the original 75mm stroke yields a 4mm difference; meaning the piston will be drawn 2mm further down thed bore and pushed 2mm further up the bore. Aside from that more crown volume is needed if you wish to preserve stock compression.
Bottom Line, if you put stock 2.0L pistons in with a 79mm stroke crank the pistons will hit the heads; hence the need for a "stroker piston".
The sttroker pistons is basically a 2.0 bore, with a 2.5L compression height.

Oh, and on the subject of Oil/pumps. I would use a 10mm pump for your application especially considering the fact that you do not have AVCS.
On my 2.1 with Mahle pistons I used Shell Rotella T 15W-40 for break in oil and it worked great. the rings seated fast. The motor never smoked and I never had to add any oil between changes. That being said, what are your planned clearances? I would not run a 40 weight oil unless you plan to run larger than stock clearances.

[brutnus]

Originally Posted by Spenk

No, as in not. The stock tune is now as useless to you as a screen door on a submarine.

Your stock map requires a stock car for proper operation. What you will have is a long, looong way from that.

You need a tuner to help you with A) initial fire-up map, B) low-boost break-in map, C)final tune.

The break-in oil will need to changed after the initial start-up, then at least once again before the final tune.

Wow did a quick search and there are 2 opposing opinions on how to break in a motor. Easy or Hard.

Specificly this thread.

[clegg318]

you guys are making me a little weary about the map i was planning to run for my break in, the set up for my 2.1 is gunna run a vf39, pinks, and a sti tmic, i was initiall gunna use cobbs ots map for this setup on a 2.0 since it tunes by target afr and not injector pulse with, so in theory it should seek the proper afr despite the 100cc difference in displacement. i called precision tuning and asked them what they throught of the idea and they agreed that since the car is tuned for target afr that it would be fine to run this map for a break in as long as i stay out of boost. i imaging i could always go in and back off the boost solenoid duty cycle to keep me out of boost too for extra precaution

[NITROS]

You would be fine with OTS map as a breakin map. the extra displacement is just going to make your hit load sites you normally wouldnt with a 2.0. the car will fireup no problem.

[brutnus]

just my thoughts (again not a car guru).

If the engine isn't knocking and the car is hitting correct A/F ratio why couldn't the stage 1 map not work?

Maybe not ideal performance but still.

[clegg318]

oh i have no doubt the car will fire up just fine, i figure as long as im not pushing the engine and i watch my afr's i should be ill be fine, ill just put on 1500 miles back and forth from work, change the oil at 100, 500, and 1000 miles and then pay a visit to precision tuning to dial her in.

[Concillian]

Originally Posted by brutnus

just my thoughts (again not a car guru).

If the engine isn't knocking and the car is hitting correct A/F ratio why couldn't the stage 1 map not work?

Maybe not ideal performance but still.

The point is that the engine will be knocking.

By changing the stroke, you change the VE curve. Especially in lower RPMs where you'll be cruising and breaking it in on moderate boost. When you increase VE, you tend to lower the amount of timing advance the engine wants. Thus, the previous map will have more timing than you want... which almost certainly will result in knock.

Using a 75mm stroke map with a 79mm stroke engine is setting yourself up for cruise and spool knock.

This is not a huge deal if you transcribe to breaking it in super easy, but most like some moderate boost and vacuum to seat the rings. With 75mm stroke mapping, you will not want to enter boost at all, staying in load cells that are as low load as possible. It will run, but it won't run well enough to break it in, and you want to be able to break it in with some boost and vacuum as quickly as possible.

oh i have no doubt the car will fire up just fine, i figure as long as im not pushing the engine and i watch my afr's i should be ill be fine, ill just put on 1500 miles back and forth from work, change the oil at 100, 500, and 1000 miles and then pay a visit to precision tuning to dial her in.

1500 miles is not something you want to have a potentially knock happy tune for. AFRs are not the issue at all. You can stay in closed loop and let the ECU worry about AFRs, even for some low boost / high vac break in. The issue is the timing map.

[clegg318]

so what do you suggest would be the best route, should i go into the ots map and take the timing back say like 3-5 degrees maybe more across the board and then leave the boost solenoid duty cycle alone so i see some low boost for the break in period

[cha86]

imo 15w40 is an awfully thick oil to break the engine in. i would stick to cheap 5w30 for at least 100 miles

[cha86]

Originally Posted by brutnus

So first crank on the new engine is the stock ecu ok for handling this? Custom low boost break in map, outside of the boost is there anything else that needs to be changed? if not i can baby the car around for the first 300 miles.

dont baby for 300 or you will have a oil happy engine. ring break in is less than 50 miles of operation. get those babies seated with some healthy boost and lots of decel to pull them rings down on the wall.

[Spenk]

^^^^ Word.

Hard break-in all the way, provided you give the engine some run-in time to be certain everything's happy.

With my build, the tuner ran a low-boost map and then a higher-boost (but not full) in the first 50 miles with an oil change done between map swaps to look for trouble. He ran the car on the mid-boost tune until 150 miles.

Another oil change and I was putting the whip to it HARD after the first 150 miles of break-in and oil changes.

Full boost, full throttle, assloads of engine braking and the engine burns no oil after 24K miles.

Brutnus: you should probably add a turbo inlet and possibly a Crawford or Ixiz AOS (delete the PCV valve -- you don't need it).

[Concillian]

Originally Posted by clegg318

so what do you suggest would be the best route, should i go into the ots map and take the timing back say like 3-5 degrees maybe more across the board and then leave the boost solenoid duty cycle alone so i see some low boost for the break in period

Yes, pull timing or get a tuner's break in map. If you look back at the responses in this thread, there have been several recommending a specific break-in map. pulling timing yourself is a substitute for that.

Break in you can see in the big thread on it. I live near a nice long hill. I can warm the car up on the way to the hill, get a nice long pull up at 2.5-4k RPM at 5+psi, then a nice long decel on the way down. Turn around and you get it again. Alternate moderate boost and max decel as early as you can in the break in to get a good seal on the rings.

Once you get a chance to do that, drain the oil and you can drive "normal" for as long as you feel necessary for remainder of break-in. I think the 2nd part of break-in is much less important than the initial ring seat.

[Joelo_00]

What kind of HP and torque can we expect from a forged 2.1 stroker? Compared to a forged 205

[KpT KiM]

Cool build! I would do the TGVs but only if you can save a lot of money and do it yourself.

Why are you going with a new pick up?

[KpT KiM]

Originally Posted by Joelo_00

What kind of HP and torque can we expect from a forged 2.1 stroker? Compared to a forged 205

Torque figures will be different, and peak power will be lower in the RPMs. Plus he'll have almost 2.5 like spool.

[Concillian]

Originally Posted by Joelo_00

What kind of HP and torque can we expect from a forged 2.1 stroker? Compared to a forged 205

HP is largely dependent on the turbo and heads. EJ205 heads are what they are, and a stroker isn't going to change that.

If you think about the EJ205 vs. the USDM 2.5L engines (EJ255 and EJ257) there are four main differences:
- heads have better cams ... results in better flow at high flows, usually meaning better peak HP. Partly made possible from AVCS due to emissions.
- Stroke is longer ... shifts torque curve left, more power in the low end, better cruise fuel economy, slightly lowers redline.
- Bore is larger ... results in more power everywhere if there is turbo flow to support it. Heavier pistons will slightly reduce VE at very high RPM. Displacement directly impacts fuel economy
- AVCS ... can result in 20-25% more torque in the low end. no loss of high end power. Usually improves fuel economy.

A stroker addresses one of these (stroke), a hybrid addresses two (stroke and displacement). People think displacement is the biggest benefit to driveability and feel, but AVCS and stroke are almost certainly bigger contributors. AVCS is huge for low end torque and drivability, and why EJ207 swaps are a popular option as well.

[Spenk]

Originally Posted by KpT KiM

Cool build! I would do the TGVs but only if you can save a lot of money and do it yourself.

Why are you going with a new pick up?

Time to get your learn on HERE.

[KpT KiM]

Originally Posted by Spenk

Time to get your learn on HERE.

Ok. How do you know if your tube fails?

[Spenk]

Originally Posted by KpT KiM

Ok. How do you know if your tube fails?

Seriously?

From the link I provided, you should be able to surmise what happens "if your tube fails."

[KpT KiM]

Ok so a legitimate crack occurs. You could have just said so instead of replying with .

Now let's not take over this guy's build thread.

Good luck with the 2.1 stroker!

[FuJi K]

I stress that you take out all oil galley's on the block and clean the galleys out well.

[OrbitalEllipses]

Instead of DIYing TGV deletes or buying them from GrimmSpeed, I'd suggest a V8 manifold. Good thing I have one for sale too! /shameless plug

Sell the Cobb AP and go for an OS tune on the 2.1, also I would suggest an 18G sized turbo.

[brutnus]

Originally Posted by KpT KiM

Ok so a legitimate crack occurs. You could have just said so instead of replying with .

Now let's not take over this guy's build thread.

Good luck with the 2.1 stroker!

Lol thanks.