NA Piston Options

[MikeMan]

I have just been brainstorming for piston ideas and came up with this, not sure if it would work but it might be worth looking into.

Wiseco list the 3TC (+160 thou) Pistons with a 10.2-10.9 CR.
Bore size: 3.504" / 89.00mm
Comp Height: 1.375" / 34.92mm
CR: 10.2-10.9 @ 63cc (0.040" / 1mm Gasket)
Pin Diameter: 0.866" / 22mm

The 1UZ-FE standard piston is:
Bore Size: 3.44" / 87.50mm
Comp Height: 1.350" / 34.29mm
CR: 10.0 @ 43cc (0.052" / 1.3mm Gasket)

So with that basis I think we should be able to machine a couple of sets to give a 12.0-12.5 CR by playing with valve pockets and head gaskets.

Let me know what you guys think of this idea.

 

[Zuffen]

Mike,

You're looking at a 1.5mm bore increase in liners with a 2mm wall thickness. This would reduce the wall to 1.25mm.

I think that's getting a bit thin.

 

[MikeMan]

Mike,

You're looking at a 1.5mm bore increase in liners with a 2mm wall thickness. This would reduce the wall to 1.25mm.

I think that's getting a bit thin.

Ahhh OK

I thought the liners were 3mm.

I figured 2.25mm would be enough.

So it would only work with a resleeve, probably not worth it to only get 89mm.

 

[Lextreme II]

Mike,

Would it be cheaper if we get custom pistons for the N/A high compression pistons? You can get standard replacement with .027" MLS gaskets. I am not sure how much .027" from the standard .051" would increase compression, but that also might a method too. Can you calculate the final compression ratio with .027"?

 

[1UZ-HZ]

ACL in australia make "high compression" forged pistons, they are 10.5:1, but with .027" gaskets it should be getting close 11:1.

 

[Lextreme II]

Perhaps we can also shave the heads to increase more compression.

 

[MikeMan]

That would work.

0.027" gaskets with the ACL pistons and a small shave of the head should give 11.2-11.5:1.

That is probably high enough to get good power from it.

Do you know if ACL do those pistons in OS sizes?

P.S.

If we assume that +0.020" pistons are available and that 11.2:1 is the final CR there is still 443BHP @ 7500 and 384LB ft @ 5000.

That is not bad from a NA 4.1L V8.

 

[Lextreme II]

Mike,

Would the 11.5 to 12:1 compression might have valve problems if the timing belt break? Would 92 octane fuel be ok on this high compression pistons?

 

[MikeMan]

With an after market ECU with knock control I cannot see it being an issue at US 92 Octane (96-97 over here for that grade of gas.)

It probably would make it an interference engine, but changing the belt at reasonable intervals will minimise the risk.

I think this is the way I will go with my second engine, however it looks like I might have to dry sump the engine in my car as no factory sump will fit, I have a steering arm behind the crossmember and an anti-roll bar in front.

 

[rarson]

I don't think 1.25mm would be a problem. That's more than half the original thickness, and in an N/A application, I think we can sacrifice a bit of sleeve thickness.

If I ever get my hands on a 1UZ, I'll bore it out to 89mm and tell you guys how it went.

 

[V8Rangee]

re sleve to 5+ ltrs

has anyone here ever had it re sleved to a much larger size ... like 5 ltr ...
I know of a guy in sydney through another guy, who was getting 1300 hp with twin superchargers one roots and one centrifical, had it in a boat, then changed classes and put the motor in his car but could not drive it ...
apparenty it had been re sleved to a 5.4 ltr...
just want to know if anyone had done it ...
cheers

 

[svsgt1]

What will the compression ratio be with stock internals but with the .027" head gasket? And how is that power figure of 443hp at 7500rpm computed? Is that with a certain cam that can make power up at the range or an open exhaust or is that just a rough guess with stock parts? I ask because I would really like to make 400+ hp in my car with a cam upgrade and higher compression ratio. My car already has headers, open exhaust, and Link 5 ECU. Do you think it is possible to make 400-450hp with that plus a high compression ratio and cams?

Thanks,
Adam

 

[V8Rangee]

yes .... i have been speaking to a mate who is into the offshore power boat racing scene ... has twin 950 horse power chevs in his 42 foot boat, and he claims that when Toyota first produced the 1uzfe it was putting out somewhere int he range of 600 hp and was de tuned for the vehicle ....
with god intake and exhast and a programable ECU .. most important ... i would not do any major work on an engine for big gains with out controlling its brain ... think about the procedure,
cheers

 

[MikeMan]

What will the compression ratio be with stock internals but with the .027" head gasket? And how is that power figure of 443hp at 7500rpm computed? Is that with a certain cam that can make power up at the range or an open exhaust or is that just a rough guess with stock parts? I ask because I would really like to make 400+ hp in my car with a cam upgrade and higher compression ratio. My car already has headers, open exhaust, and Link 5 ECU. Do you think it is possible to make 400-450hp with that plus a high compression ratio and cams?

Thanks,
Adam

The figure was computed with Dyno 2000 using Kelford 207-C cams IIRC, I can check when I get home if you like.

 

[svsgt1]

Yes, that would be great. Thanks. I"m curious to see if I can get a 9000rpm cam with the shim under bucket conversion, raise the compression ratio with the .027" head gasket and get about 450hp. Now I just need to wait and hear back from the cam people to see how much the shim under bucket conversion costs.

Thanks,
Adam

 

[MikeMan]

OK

If we use the ACL Pistons in +0.5mm (20 Thou) OS and use the SBC rods (Whatever material they are made from) to get 88mm x 84.5mm, Ported heads with std valves, 207-C cams from Kelfords and Damien's ITB setup with blacktop bodies we should see ~420HP @ 7500 RPM and ~360lb ft @ 5000 RPM.

If anyone wants a PDF of the graph just drop me an e-mail at the address in my profile.

 

[svsgt1]

MikeMan, I got 3 questions for you.

1) What would a stock engine with straight through race exhaust and headers make with just Kelford 207-D cams up to the 8000-9000 rpm range with and a raised compression ratio with the .027" head gaskets?

2) What would a completely stock engine with straight through exhaust and headers and the following cam specs produce:
Duration @ Seat to Seat = Inlet(270) & Exhaust(284)
Duration @ .050" = Inlet(206) & Exhaust(210)
Valve Lift @ 1 to 1 = Inlet(0.341") & Exhaust(0.333")
Centerline @ Full Lift = Inlet(108) & Exhaust(112)

3) What would a stock engine with straight through exhaust and just a Kelford 207-C produce?

My car has the second setup so I'm curious to see how accurate it is. I'm running a really conservative max timing advance of only 28 degrees and I"m making 220rwhp. I should be making hopefully closer to 300 flywheel hp with more timing advance. But we will see about that.

Thanks,
Adam

 

[svsgt1]

I have no clue why the Centerline @ Full Lift line came out the way it did with the Red X picture box. Anyway, the specs for the Centerline @ Full Lift are Inlet = 108 AND the Exhaust = 112.

Adam

 

[MikeMan]

MikeMan, I got 3 questions for you.

1) What would a stock engine with straight through race exhaust and headers make with just Kelford 207-D cams up to the 8000-9000 rpm range with and a raised compression ratio with the .027" head gaskets?

2) What would a completely stock engine with straight through exhaust and headers and the following cam specs produce:
Duration @ Seat to Seat = Inlet(270) & Exhaust(284)
Duration @ .050" = Inlet(206) & Exhaust(210)
Valve Lift @ 1 to 1 = Inlet(0.341") & Exhaust(0.333")
Centerline @ Full Lift = Inlet(108) & Exhaust(112)

3) What would a stock engine with straight through exhaust and just a Kelford 207-C produce?

1) Dyno2000 does not like the 207-D Cams, I suspect that the head flow is to low to get a good pull on them, this program is really focused at Ford/Chev V8's and has some limitations when it comes to multivlve modeling.

2) 321HP @ 6500RPM, 312lb ft @ 4500RPM

3) 308HP @ 6500RPM, 290lb ft @ 4500-5000RPM

 

[svsgt1]

Do the power figures that Desktop Dyno give have a timing associated with them? Like is that 321hp figure at 36 degrees advance or something else? Does it take into account detonation or type of fuel or anything like that. I'm running 93 octane pump gas but I'm sure I can get 321hp on race fuel and a lot of advance, but just curious as to what the program says.

Thanks,
Adam