3.3 engine?
- Thread starter shaldaya
- Start date
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luigisho
SHO Member
Overbore isn't a secret. You just have to make sure it doesn't compromise anything. I only know of 1 3.3L on here unless I forgot another.
The question i really had was where they got the pistons, and if they used stock rods
My actual goal is to bore it to 3.3, then destroke it to 3.0 and rev the absolute living **** out of her
Sent from my SM-G991U1 using Tapatalk
My actual goal is to bore it to 3.3, then destroke it to 3.0 and rev the absolute living **** out of her
Sent from my SM-G991U1 using Tapatalk
The stock piston diameter for the 3.2 is 92mm. To get to a 3.3L you need oversized pistons measuring 93mm. You can order the pistons from Wiseco directly from SHOnut. You can get them in stock compression, low compression, or high compression. You work with Josh to accomplish what you are looking for. The stock rods are used with the Wiseco pistons.
I had a really healthy 3.3L that was 10.6:1 compression. It might be the same one that @luigisho is remembering. It was mounted in my white 89 for a long time. I removed it and replaced the pistons with 11.5:1 Wisecos with the intent on putting it into my 91+. When those plans changed to low compression boost I ended up selling my 3.3 to another forum member. My old 10.6:1 pistons were passed on to a different forum member and they are in another 3.3 that he had built.
My Moonlight Blue 95 has 93mm high compression Wisecos with modified small block Chevy rods. Those combined with the stroker crank are what bring it up to a 3.4L
It was because I bought the blue 95 that I decided to do boost in the 91+. My initial build plans on my old 3.3 were to up the compression so that I could compete with the Moonlight 3.4. When I ended up owning the 3.4L I didn't see the need for two HC cars.
-Chad
I had a really healthy 3.3L that was 10.6:1 compression. It might be the same one that @luigisho is remembering. It was mounted in my white 89 for a long time. I removed it and replaced the pistons with 11.5:1 Wisecos with the intent on putting it into my 91+. When those plans changed to low compression boost I ended up selling my 3.3 to another forum member. My old 10.6:1 pistons were passed on to a different forum member and they are in another 3.3 that he had built.
My Moonlight Blue 95 has 93mm high compression Wisecos with modified small block Chevy rods. Those combined with the stroker crank are what bring it up to a 3.4L
It was because I bought the blue 95 that I decided to do boost in the 91+. My initial build plans on my old 3.3 were to up the compression so that I could compete with the Moonlight 3.4. When I ended up owning the 3.4L I didn't see the need for two HC cars.
-Chad
That seems like a lot of work to do something the engine can already do. The rotating assembly in the Yamaha V6 can out rev the intake manifold as it is. The crank and rods aren't what's holding it back.
-Chad
Apart from the belt driven accessories
What is it that holds it back from revving higher??
If you tune it to remove the the rev limiter you can rev it as high as you want. The intake manifold cannot supply enough air flow to provide power past the stock redline unless you are pushing big boost. I haven't had my car Dynod yet, but I'm pushing 18lbs at 6500 rpm. I don't go any higher than that because #1 the accessories, and #2 I'm already at the rev limitations of the supercharger.
When my Moonlight 95 3.4 was Dynod a few years ago you can see the power start to drop off right around 6800rpm. There isn't any point in going past that.
-Chad
I know about losing power from parasitic loss. My biggest curiosity is how to reduce those parasitic losses
My information may be off, but i heard that destroking it could help improve high rpm torque
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The intake manifold cannot provide enough airflow to create power past the normal rev range. Power drops off once you get into the 6ks of the power band. You can rev it to the moon if you want but you won't be making any power.
-Chad
Ah, okay, intake is the problem
Sounds like id basically have to redesign the intake manifold for what i am thinking
Thats definitely outside my price range
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A custom intake would be cheaper than a custom crankshaft.Ah, okay, intake is the problem
Sounds like id basically have to redesign the intake manifold for what i am thinking
Thats definitely outside my price range
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Building a forged low compression 3.3 currently.
There is one available that Zach had made. Not sure if anyone is selling theirs.Ah, okay, intake is the problem
Sounds like id basically have to redesign the intake manifold for what i am thinking
Thats definitely outside my price range
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He actually made more than 1 of those? I would absolutely love to get one of those intakes
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A few thoughts on this subject -
The limit on overboring is the 3.2L head gasket, 93.25 mm. Only one set of custom head gaskets ever made, to get to 3.5 with an offset ground crankshaft, and that required sleeving a couple of the bores. I think the fire rings came from a Chevy application.
Problem with offset grinding the crankshaft a significant amount is that you lose the factory nitrided surface. Yes you can re-nitride after offset grinding but at risk of the crank warping.
Ernie's land speed attempt using a SHO engine involved an overbore stock 3.0L; 89 to 90 mm and then a "cheater destroke" (using the max undersized rod bearings) to keep him at regulation 2,999 cc's. This did alter the rod stroke ratio a small amount. Extrude honed intake and aftermarket cams allowed for making power above 8 krpm.
On the subject of the stock intake I looked at taper boring the throttlebodies to get an extra 1 mm in diameter at the throttle shafts (42 mm, vs. 41 mm for SHOshop and 40 mm for most other places), and then "half shafting" by lightly milling half the throttle shaft, in order to increase the area at this pinch point (increase flow on the short runners). This might be good for 500-1000 rpm higher power band once the secondaries open. Requires complex machining of the throttle plates. The opening at the plenums, finding the right size air horns, was a challenge.
Some have acid etched out the plenums to increase their volume, tricky, dangerous to do.
Seems like using factory parts one can get to right around 3.3 liters using the max undersize rod bearings to increase stroke and compression ratio a little, along with a 93 mm overbore.
As far as reducing parasitic loses, titanium valves, possibly with a little lighter valve spring would be the way to go.
The limit on overboring is the 3.2L head gasket, 93.25 mm. Only one set of custom head gaskets ever made, to get to 3.5 with an offset ground crankshaft, and that required sleeving a couple of the bores. I think the fire rings came from a Chevy application.
Problem with offset grinding the crankshaft a significant amount is that you lose the factory nitrided surface. Yes you can re-nitride after offset grinding but at risk of the crank warping.
Ernie's land speed attempt using a SHO engine involved an overbore stock 3.0L; 89 to 90 mm and then a "cheater destroke" (using the max undersized rod bearings) to keep him at regulation 2,999 cc's. This did alter the rod stroke ratio a small amount. Extrude honed intake and aftermarket cams allowed for making power above 8 krpm.
On the subject of the stock intake I looked at taper boring the throttlebodies to get an extra 1 mm in diameter at the throttle shafts (42 mm, vs. 41 mm for SHOshop and 40 mm for most other places), and then "half shafting" by lightly milling half the throttle shaft, in order to increase the area at this pinch point (increase flow on the short runners). This might be good for 500-1000 rpm higher power band once the secondaries open. Requires complex machining of the throttle plates. The opening at the plenums, finding the right size air horns, was a challenge.
Some have acid etched out the plenums to increase their volume, tricky, dangerous to do.
Seems like using factory parts one can get to right around 3.3 liters using the max undersize rod bearings to increase stroke and compression ratio a little, along with a 93 mm overbore.
As far as reducing parasitic loses, titanium valves, possibly with a little lighter valve spring would be the way to go.
To which 3.5 are you referring Zack?
John M's (California based build, think a white 91+ 91+ ?) JEM on this list. The custom gasket maker he hired did not want to do another.
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