Testing The Waters

[SmsAlSuwaidi]

And yet people with 2js are increasing CR with mutated watermelon sized turbos


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[diss7]

Originally Posted by Jason@DSG

There's no stroker kit that's worth making. You can make more displacement with overbore. We already outweighed the value. It will barely make a difference and the cost for the crank is going to be not worth it IMO.

I even confirmed with BC, there's no worthwhile stroker possible. A boxer engine layout doesn't leave enough clearance with the rod shape to allow more stroke.

Toda kits will be 2250cc. That is significant.

Tomei already offer 'crate' boxer motors, with increased displacement. I have also heard whisper about Tomei preparing to offer built FA20's, ready to go. Although I dont know any details or time frames.

I had a Tomei SR20 about 8 years ago. It cost a lot, over $12k NZD, when I could have had one built locally for maybe $7k - $8k, but I paid for the name. And I wasn't disappointed. That motor was a honey.

Edit - Link for Tomei crate motors - http://www.tomei-p.co.jp/_2003web-ca...m-genesis.html

[wparsons]

Originally Posted by Jason@DSG

It's a combination of both. Good internals but why do you think factory CR is 8.0:1? There's a reason they didn't go with anything higher. The reason IS lower compression allowing higher boost.

I have 9.0:1 in my car at 30psi making 500whp on a twin clutch transmission.

On low, very low boost higher compression is okay but you cannot exceed 8-10psi without getting into the danger zone (enter Top Gun song)

I can't stress enough high boost = low compression, do you think I'm inventing this? Why do you think the STi, Evo, SRT, Most high hp muscle cars all run sub 9 CR's?

There is so much untapped power in the FA20 by lower compression and adding boost.

Low c/r is low tech, if you're running DI you can run much higher c/r safely (boosted or not). At one point 12.5:1 was extremely high for an N/A application, but now it's common. Some of the new Mazda DI engines are 14:1 range stock, they even have engines that are 13:1 that run on 87 octane.

Even the older "high compression" honda engines (ITR and CTR) are only 11.1:1, and the highest compression K20 is 11.7:1.

[Jason@DSG]

It's not low tech...lol running high compression and high boost is asking for trouble tech. Any big power is also low compression. Please get me any engine build over 450-500whp with compression over 10, please (forced induction)...that is a daily driver on pump fuel (I'm aware of all our race setups on race fuel -- I'm talking every day cars running 91 or 93 oct)

[nelsmar]

Originally Posted by Jason@DSG

It's not low tech...lol running high compression and high boost is asking for trouble tech. Any big power is also low compression. Please get me any engine build over 450-500whp with compression over 10, please (forced induction)...that is a daily driver on pump fuel (I'm aware of all our race setups on race fuel -- I'm talking every day cars running 91 or 93 oct)

Im building 11:1 but.... I daily on E85. And will be turning the boost down significantly on E85. So I can agree to an extent. Big power on piss fuel requires low compression!

[FreshFRS]

i agree with most of the guys here, i mean my s2k went turbo (built motor but 11.5:1 comp) and i ran 15psi on pump gas through it with no problems and for lots of kms (<75,000) i drove it hard too and in winter. a better example in the Cobalt SS/TC 2.0 Ecotec, DI with 10.5:1 compression guys are running 400+whp out of 24Psi on the stock block with pump gas (94 here in canada), 9:1 is overkill and is going to kill off boost response. unless you want 40+psi with lots of lag anyway i really don't see anything less than 10.5:1 being viable for the street. this is all IMHO anyway.

Power on the s2k was 445whp/305tq @15psi is what we settled on, 18psi needed meth injection to be liveable. though we managed to make a couple runs without meth. This is on Engine without DI or VVT (VTEC kicked in at 4300 and only has 2 profiles) which would increase the boost threshold for sure. @Jason@DSG

Also food for thought, s2ks that had lowered compression(8.8-9:1) are running 5-7psi more than this car to produce the same power/torque. stock 11.3:1 compression blocks have generated 520+with 93+ meth at 17-18psi, 701/450 at 27psi on 116 and 740/470 on E85 at 30psi.

[diss7]

FWIW I don't disagree than lower compression allows more boost. But I feel the trade offs are not being fully disclosed.
Lower static comp will need more boost to get the same power level.
Lower static comp is not as responsive.

There was a comment that small turbos are boosting so early that this would not be an issue. I disagree for two reasons. One, you are talking about full throttle only. Two, if you have a small turbo, you can already exceed its capacity on a stock motor.

Low comp is for big power. That means big lag. Big lag and low comp, sucks on the street. Big time.

Do it if you want. It's either a dyno queen, a highway puller, or for online bragging. Or you've spent $30k in supporting mods, replacing the entire drivetrain, suspension, brakes, fuel system, to make a weapon. But, thats the least likely.

[Jason@DSG]

Originally Posted by diss7

Toda kits will be 2250cc. That is significant.

Tomei already offer 'crate' boxer motors, with increased displacement. I have also heard whisper about Tomei preparing to offer built FA20's, ready to go. Although I dont know any details or time frames.

I had a Tomei SR20 about 8 years ago. It cost a lot, over $12k NZD, when I could have had one built locally for maybe $7k - $8k, but I paid for the name. And I wasn't disappointed. That motor was a honey.

Edit - Link for Tomei crate motors - http://www.tomei-p.co.jp/_2003web-ca...m-genesis.html

Exactly...waste of time. Clearly you didn't calculate displacement with overbore (0.7854 x B2 x Stroke x # of Cyl)

Do you know what 90mm pistons do on this engine? 2200cc almost, stock crank.

Therefore you're going to pay insane amounts for a custom forge crank/labor in machining + special rod/main bearings to gain barely any torque and lose out on high rpm potential. It's 0.05L extra which is nothing and high rpm will not be possible when valve train items come out.

Stroker = waste of time on this engine

Power to anyone who wants to make it but it's not worth it on this platform IMO 90mm pistons makes an almost 2.2L engine and considering that's sleeved, you could put a really nice turbo on there and make serious power

[diss7]

Originally Posted by Jason@DSG

It's not low tech...lol running high compression and high boost is asking for trouble tech. Any big power is also low compression. Please get me any engine build over 450-500whp with compression over 10, please (forced induction)...that is a daily driver on pump fuel (I'm aware of all our race setups on race fuel -- I'm talking every day cars running 91 or 93 oct)

IMO you are comparing this motor to motors that are at least 10 year older designs, some 20. Its not apples for apples.

If you want high boost, low quality fuel, yes low compression is the way to go. I just dont get it. If you need that much power, you spend the money. But too tight to buy proper fuel?

I'm sure there will be a market for your product regardless, which is really the point of this thread.

[SmsAlSuwaidi]

[ame]http://youtu.be/a15CKX-uJP8[/ame]




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[Jason@DSG]

I guess the R35 has it wrong too at 9.0:1, maybe someone should let the guys making 1600-2000hp know that the experts here recommend 12.5:1 or higher to make big power, they're definitely missing out

http://en.m.wikipedia.org/wiki/Nissan_VR_engine

[Jason@DSG]

Originally Posted by diss7

IMO you are comparing this motor to motors that are at least 10 year older designs, some 20. Its not apples for apples.

If you want high boost, low quality fuel, yes low compression is the way to go. I just dont get it. If you need that much power, you spend the money. But too tight to buy proper fuel?

I'm sure there will be a market for your product regardless, which is really the point of this thread.

You're joking right?

Even that Supra is 10.5 and that's a VERY expensive engine to make that happen. It's also in the 10 range of compression like I said. You guys are actually trying to say 12.5 is good to make power. I think you need to keep reading up.

As I said, the Nissan engineers must be idiots doing 9.0:1 on the GTR's making 1600whp.

[diss7]

Originally Posted by FreshFRS

i agree with most of the guys here, i mean my s2k went turbo (built motor but 11.5:1 comp) and i ran 15psi on pump gas through it with no problems and for lots of kms (<75,000) i drove it hard too and in winter. a better example in the Cobalt SS/TC 2.0 Ecotec, DI with 10.5:1 compression guys are running 400+whp out of 24Psi on the stock block with pump gas (94 here in canada), 9:1 is overkill and is going to kill off boost response. unless you want 40+psi with lots of lag anyway i really don't see anything less than 10.5:1 being viable for the street. this is all IMHO anyway.

Power on the s2k was 445whp/305tq @15psi is what we settled on, 18psi needed meth injection to be liveable. though we managed to make a couple runs without meth. This is on Engine without DI or VVT (VTEC has 2 settings not variable) which would have increased the boost threshold for sure.

This.

My 3SGE Blacktop is 11.0 CR and 400whp at 14psi, 430whp @ 16psi, but dialed it back as turbo was working too hard. All on pump fuel. When I had the motor built, I was honest with my engine builder, with respect to power goals. If I had've said 600whp, he wouldve said sleeves, crank, and lower comp.

Edit - Sorry my 3sge is actually 10.5CR, just looked up the invoice and rang my engine builder.

[diss7]

Settle down guy.

No one is saying 12.5CR is okay for crazy power.

9.0CR is ideal if running CRAZY boost, for CRAZY power. Like the examples you have listed above. But is this really your target audience? No of course not. Anyone with pockets that deep isn't getting off the shelf parts.

Your target market just selling pistions and rods is to people trying to get a built motor on the cheap. Maybe 400 - 500whp. They're not R35 owners, or 1600whp owners.

Set whatever CR you want, its your business. Just don't expect to put out information on a public forum, then get butt hurt when you get differing opinions.