Performance engine builds

[thornz]

This is a bit of a dummy question I'm sure. But could someone enlighten me as to what bits are desirable for a performance rebuild? I have just purchased a MR2, so the engine is a 3sgte. In the future I have though about perhaps a rebuild, so what parts do I want? I know the obvious parts like forged rods and pistons, but what else it generally done at the same time? Its something that If I decide to do it, I might just start colletcing bits as funds permit. So if you were building a forged/performance motor, what would be on your shopping list? And a rough price guide would be helpful also.

[IH8TEC]

allow 2-3500 for a good headjob as that will make the power, cams, springs, porting, cam gears etc all to suit the form of racing you wanna do.

[rollaholic]

what you do really depends on what you want to achieve.

rebuilding to standard specs will be fine (and alot cheaper) if your goal is none to mild power gains. however if you want to run 10 second quarters or something then a slightly different approach will be needed...

so perhaps if you were more specific about what you want out of the car?

[Dell'Orto]

Get the entire rotating mass balanced, its not terribly expensive and it makes for a much nicer engine.
Again, really depends what you want from the engine, 3SGTE's are pretty tough so unless you want huge horsepower a stock rebuild will be pretty good.

[thornz]

Well, realistically I am not after huge power, always just fancied a reliable street driven 350hp, which obviously is not that hard to achieve. So I guess a pretty basic build would be all that would be required. Dont know if I would be worried about cams etc. With that power figure in mind, would it pretty much be a case of making the internals bulletproof, forged rods and pistons?

[MR2BOY23]

Im sure you wouldnt need bulletproof internals for 350hp

[Dell'Orto]

350hp would be a doddle with the right turbo, price up Gen3 pistons and use those, the rods will be sweet.

[thornz]

So spending money on forged internals would not be worthwhile? Be better just having a fresh build with standard internals?

[MR2BOY23]

So spending money on forged internals would not be worthwhile? Be better just having a fresh build with standard internals?

350hp would be a doddle with the right turbo, price up Gen3 pistons and use those, the rods will be sweet.

[Dell'Orto]

Wouldnt bother with forged rods, no. Forged pistons maybe, but Gen 3 pistons are quite good and cheap.
Spend your money on the head, thats where you'll make power.

[deaf_rattle]

with my build, i basically just went with a stock rebuild on the head.
Spend the time and money, get it done right.

For what you are after, i wouldnt bother with porting, aftermarket cams etc.
Just stock specs.

Bottom end, id get forged pistons, shot peen the rods and use Arp fasteners and get the whole rotating assembly balanced.

put together with a decent mhg and stock gasket set and you will be away laughing.

Sort out fueling and turbo, and you are done.

[Adydas]

look at $9000 bucks easy if your seriously considering going hole hog and then it resembles somthing like this http://adydas.net/main.php?g2_itemId=216 that said theres still things i havent done.. Not to mention after been done the head gaskets blown once and possibly a second as well as the release bearing on the clutch going so it forever costs big bucks and its not even a highly powerfull car / motor / ecu / setup.

Ive spent $1600 cams, $4000 on the bottom end $1600 on turbo.. List goes on and on... big $$ into a 3sgte and while im happy with the results i cant excatly say its justified...

If you really have money to spend and want to do somthing the BEST thing i did was buy some tein adjustables.. Not only does the car handle better but it also feels faster beacuse it reduces the saggy feeling when you plant your foot..

[iOnic]

You don't *need* forged rods/pistons for 350hp. I'd get it rebuilt to factory specs if I was in that situation and then focus on turbo choice + fuelling + ecu. At 350rwhp you're about 100 away from testing a [good condition] factory 3sgte bottom end's limits

As was mentioned above somewhere, spend time/money on the suspension side of things to make use of the power you already have. You'll probably find with better suspension and wheels/tyres that the car feels plenty fast as it is or with slightly more than factory power output. Bear in mind you don't need stupid amounts of power to go fast........slightly over the 400whp mark is 10sec territory in MR2's

[Boosted_162]

This is what id do. Standard rebuild

- Stock pistons rods - perhaps gen 3 pistons as above).
- Metal headgasket - gen 3 3SGTE stock comes with a metal one - use it .
- Cam grind from Kelfords/wherever
- Use ARP bolts for assembly, and maybe ACL race bearings.
- ECU - if gen 3 stock, PowerFC (its plugin). Gen 1-2 Link ECU/Motec etc.
- Injectors - gen 3 motor - stay stock, gen 2 - get gen 3 540's

If your getting into circuit racing, id definately recommend oil pan mods, or an accusump to stop bearings going!

[iOnic]

OT: What's the difference between Gen2 and 3 pistons?

[Boosted_162]

OT: What's the difference between Gen2 and 3 pistons?

IIRC its what changes the CR between the generations. Fivebob should be along soon with the best advice

EDIT: I see gen 1 shares the same CR (8.5:1) so not sure if pistons are the same? Gen 2 has a lower CR of 8.1:1

[frost]

350hp would be a doddle with the right turbo, price up Gen3 pistons and use those, the rods will be sweet.

is there any difference in valve cut outs on the gen2 and gen3 pistons? seeing as they have different heads. valve angle maybe?
im rebuilding my gen2 3sgt now and that could be a cheaper option at this stage for me.

[DeeCee]

First, what year is your MR2.
Second, I know that everyone is suggesting stock gen3 equipment, so why not go for the whole gen 3 engine! Its what I did in the end after debating the whole forged, extra this that and all the rest debate.

[thornz]

Its a 91 tubby, so Gen 1. I'm not really in any hurry, would rather do it right first time than half baked, so all these opinions are good food for thought.

[DeeCee]

actually that makes it a gen 2 3sgte.