efr 6258, a good low boost option?
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After crunching numbers in regards to na vs. Fi, i think I am going to go turbo. Someofit. I autocross 10-15 events a year, and am ready for more power. The boost lag on the turbo cars I have driven made me never want one for auto cross, but I was thinking medium compression(9.5:1?) And low boost.
I have a friend who has moved on from the efr 6258, and is pushing me to use it. My questions are:
1. Is this too big to be useful in autocross?
2. My power goal is 200-220, is this a reasonable turbo for the goal?
3. Is medium compression and mild boost just lame, for any purpose?
My car- 1995 1.8, megasquirt 2, engine rebuild in progress (pending turbo selection)
Thanks,
Ryan
I have a friend who has moved on from the efr 6258, and is pushing me to use it. My questions are:
1. Is this too big to be useful in autocross?
2. My power goal is 200-220, is this a reasonable turbo for the goal?
3. Is medium compression and mild boost just lame, for any purpose?
My car- 1995 1.8, megasquirt 2, engine rebuild in progress (pending turbo selection)
Thanks,
Ryan
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If autocross is your only game, I'd recommend a supercharger. The slow top speeds and the constant off - on throttle in the turns would mean you are mostly out of the range to spool a turbo unless you get a small one. The EFR spools great, but you would be too low in the RPM range to get the most out of it.
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So you go from 101 ft/lbs to 105 ft/lbs off boost just to inadvertently limit the spark curve you can run up high? It doesn't leave you in a better place. Get a copy of Desktop Dyno software and run the compression differences to see what they give you on a BP's bore and stroke. It is negligible difference in reality. In a NA race engine where you need every 3 to 5 hp on the top end it matters a lot to run a 12 to 1 versus a 8.6 to 1. It matters much more than a 8.6 to 9.5 bump on a turbo car.
I didn't explain that well.
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Dang it, I was hoping you guys were going to tell me that this was the best turbo for my application ever. This doesn't seem to be the case though. I guess I need to go back to the drawing board. I would like to say with stock rods and replacement pistons for the rebuild. Is this just ridiculous to you then consider putting a turbo on with the stock internals?or was I just trying to put the wrong turbo on this engine?I just don't have the 2000 to drop on engine internals and 3 or 4 thousand to put down for the turbo setup. It's kind of one or the other at this piont.
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If you're going to pull the engine down and you think you might run some boost someday, seems like a no brainer to throw some rods in it.
A better turbo for your application would be a 2554 IMO.
A better turbo for your application would be a 2554 IMO.
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Dang it, I was hoping you guys were going to tell me that this was the best turbo for my application ever. This doesn't seem to be the case though. I guess I need to go back to the drawing board. I would like to say with stock rods and replacement pistons for the rebuild. Is this just ridiculous to you then consider putting a turbo on with the stock internals?or was I just trying to put the wrong turbo on this engine?I just don't have the 2000 to drop on engine internals and 3 or 4 thousand to put down for the turbo setup. It's kind of one or the other at this piont.
you want a fast spooling turbo that will be easy on the rods get a 2554 or something in that size range price range and run it on stock long block at under 10psi. should meet pretty much all yours goals.
also LOL @ not having money for rods but considering EFR
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my plan up until the other night when the turbo was offered to me,was the popular 949 recipe,. 99 head,square top, 4.37. Maybe for the autocross this is still the best option?wait a minute I forgot somebody suggested a supercharger, but they get hated on so hard around here!
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I'm not sure if you're trying to do the stupidest ting known to miata's, but you're succeeding.
you want a fast spooling turbo that will be easy on the rods get a 2554 or something in that size range price range and run it on stock long block at under 10psi. should meet pretty much all yours goals.
also LOL @ not having money for rods but considering EFR
you want a fast spooling turbo that will be easy on the rods get a 2554 or something in that size range price range and run it on stock long block at under 10psi. should meet pretty much all yours goals.
also LOL @ not having money for rods but considering EFR
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You'll spend more on the manifold for the EFR than a used 2554 + log manifold that won't bend your rods.
my plan up until the other night when the turbo was offered to me,was the popular 949 recipe,. 99 head,square top, 4.37. Maybe for the autocross this is still the best option?wait a minute I forgot somebody suggested a supercharger, but they get hated on so hard around here!
4.37 (what is this?) rear end sounds positively hideous for autocross.
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I just got my 949 twin disc organic in the mail, and the 15 by 9 949wheels should be here next week. But I see where you're going with this. So who needs a EFR for a decent price?