Stroker, High reving, spooling...

david-b · #1 10-14-2007, 10:15 PM

Engine topics!
So I've been thinking about the motor rebuild and thinking what I want to do. There's ups and downs of everything and I'm trying to decide which is best for what I want.

Originally I was going to stroke the motor to a 2.2, but then the turbo will take longer to spool, correct? Why? I always won't be able to build a high reving motor then too right? Why's that? Why is there a difference between that with a stroked motor and an non-stroked motor?

Leaving it as a 2.0, I can get revs high and spool time quicker, but isn't that going to hurt the motor more then? We all know how much these things fall apart to begin with.

So which is better to do? If there seems to be so many downs with stroking, then why do so many people do it?

tfoti · #2 10-14-2007, 11:52 PM

The more displacement the SHORTER the time it will take a turbo to spool.

This mainly applies to 4G63's but the info is still relavent.

http://www.dsmtuners.com/forums/showthread.php?t=271451

steviek · #3 10-15-2007, 03:28 AM

wow great article.

Thor06 · #4 10-15-2007, 03:45 AM

Boner!

gthompson97 · #5 10-15-2007, 01:19 PM

Stroker = faster spool, less revving
Stock = slower spool, higher revving

EDIT: Edited for retarded post. Destroker does NOT increase spool time.

Thor06 · #6 10-15-2007, 03:08 PM

I dont think the destroker spools any slower than a 2.0 does it? Theres no reason it should, afterall it has more displacement than the 2.0.

david-b · #7 10-15-2007, 04:43 PM

But why would someone perfer high high rev over quick spooling? Or vise-versa?

gthompson97 · #8 10-15-2007, 05:08 PM

Quote:

Originally Posted by Thor06

I dont think the destroker spools any slower than a 2.0 does it? Theres no reason it should, afterall it has more displacement than the 2.0.

No it does not. I posted in class in a hurry and wasn't thinking. I edited it just for you.

Quote:

Originally Posted by david-b

But why would someone perfer high high rev over quick spooling? Or vise-versa?

Personal preference. Have you ever heard a motor screaming at 11k? It's pure sex. I don't think revving to an extra 1-2k rpm gives you that much more performance, and I think people have a misunderstanding that the higher you rev the more power you can get, which is untrue. The "higher power band" wouldn't start to come in until you get into the 15k-16k rpm range, which with most car engines is highly, highly unlikely.

And I'm sure I don't have to explain why people stroke for quick spooling.

david-b · #9 10-15-2007, 05:22 PM

Quote:

Originally Posted by gthompson97

Personal preference. Have you ever heard a motor screaming at 11k? It's pure sex. I don't think revving to an extra 1-2k rpm gives you that much more performance, and I think people have a misunderstanding that the higher you rev the more power you can get, which is untrue. The "higher power band" wouldn't start to come in until you get into the 15k-16k rpm range, which with most car engines is highly, highly unlikely.

And I'm sure I don't have to explain why people stroke for quick spooling.

But in the higher rpm range, the turbo is still spooled full and running full boost. It's safer for the engine to be shifted earlier (ie 7k) then to run it up to 11k. I just don't see why (besides preference) why someone would want a high revving motor. compared to a quicker spool time if you're going to be getting the same power out of it.

cantgo2fast · #10 10-15-2007, 07:53 PM

I read a great article the other day that said "its better to make power at higher RPM to take advantage of gearing" It all comes down to preference and use. If your building a pure track car thats only gonna see less than 3k rpm at the beginning of the race isnt it better to have your power band reach higher. If your building a DD that makes absolutely no sense becasue itd be like drving a D series civic all day unless you drive like a maniac and drive to redline from every stoplight.

gsxeclipse97 · #11 10-15-2007, 11:00 PM

well... you can have a high reving stroker its weather you build your engine enough to be able to take the abuse. They do make 7-bolt strokers that can rev to 8k, but on the flip side of that you are going to need a turbo and cams that will support that kind of power. Having a stroker would be more of a if you are planning on running a super huge turbo where spool time is a big factor. For someone with a evo3 for ex that would be a bit over kill sure. Sure you would spool the turbo instantly but it would not be able to flow enough to stay with the motor, so in that case its would be more suitable for someone with a stock displacement to take advantage of that.

kjewer1 · #12 10-16-2007, 05:18 AM

Higher rev limit means you can take spend more time in lower gears over the course of the quarter mile. That means a greater percentage of the track spent at higher acceleration rate. I've posted a lot on this topic in the past. Almost every top ET DSM is running a 2 liter. To spool a big turbo on a street/strip car though, a stroker can really be the way to go.

I ran my regular 2.3 combo to 8k rpm all day long, no real issues. Above that though and you're better of with a long rod motor (2.4 block, 2.3 pistons, 162mm rods). I've heard of people with Magnus long rod motors going to 9k.

Destrokers are an interesting option. 2.1 liters with a more favorable rod ratio than a regular 2 liter. There are some funny piston speed dynamics to consider though, which have been blamed for the 2.1s lack luster performance in many cases. I'm not sold on them yet.

david-b · #13 10-16-2007, 11:30 AM

So it has a lot to do with the fact that gears 1-3 are more of acceleration gears. You want to stay in those as long as possible on the track, but for street and DD use it wouldn't make sense right?

So, since my car is a DD and will see the track every now and then, stroking would probably be good if I go with a large turbo? Any specifics on what size would be large then?

SilvrEclipse · #14 10-16-2007, 11:38 AM

Dont waste your time stroking the 420a. You would be better off to drop a 2.4 in it. Its not that much more work and im sure you would make more power.

defiancy · #15 10-16-2007, 12:59 PM

Quote:

Originally Posted by david-b

So it has a lot to do with the fact that gears 1-3 are more of acceleration gears. You want to stay in those as long as possible on the track, but for street and DD use it wouldn't make sense right?

So, since my car is a DD and will see the track every now and then, stroking would probably be good if I go with a large turbo? Any specifics on what size would be large then?

Large for what? The 2.3? The 2.3 4g63 can run a GT35R type turbo with ease and get great application out of it. That is a rather large turbo that makes really good power. How streetable it is dependent on your setup. I'm not sure if the same would hold true for a 2.3 420a, but I can't imagine it being that different in terms of turbo applications.

What are you goals with the car as a turbo? With that we may be able to point out a better turbo for your applications.

Also have you given any thought to what SilvrEclipse said about the 2.4 4g64? I mean that would be almost just as good as you having a factory turbo e-ride

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