Car Forums  

Go Back   Car Forums > Vehicle Specific > Asian Imports
FAQ Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-25-2006, 01:39 PM   #1
240SXSR20DET
CF Newbie
 
240SXSR20DET's Avatar
 
Join Date: Feb 2005
Posts: 42
turbo question

i have a 1990 miata and am about to put a t28 turbo in it, and i was wondering how many pounds of boost i can put on the stock motor without having to get a new fuel pump or some rx7 turbo fuel injectors. I am also worried about the well being of the motor so i only want to run a little bit for now but still feel a difference in the power. Any help would be appreciated.
240SXSR20DET is offline   Reply With Quote
Old 01-25-2006, 01:50 PM   #2
vlc92189
CF Newbie
 
Join Date: Jun 2005
Posts: 90
i wouldnt say no more then 10 lbs.. but google it
vlc92189 is offline   Reply With Quote
Old 01-26-2006, 11:17 AM   #3
HyundaGuy
Relicensed n ready 2 race
 
HyundaGuy's Avatar
 
Join Date: Jul 2005
Location: Adelaide, SA, Australia
Posts: 674
Quote:
Originally Posted by 240SXSR20DET
i have a 1990 miata and am about to put a t28 turbo in it, and i was wondering how many pounds of boost i can put on the stock motor without having to get a new fuel pump or some rx7 turbo fuel injectors. I am also worried about the well being of the motor so i only want to run a little bit for now but still feel a difference in the power. Any help would be appreciated.


none, sell the T28 and buy a turbo kit from a tx3 laser/escort, your engine would be a 1.8ltr? yeah? then it's a BP engine, thus meaning that here in aus, ford brung out a bpT version, 1.8ltr dohc, turbo, efi, fmic blah blah blah, the works, tough car.

i wouldn't even bother trying to put such a powerful turbo on a stock engine, even the worked ones that i've seen in laser's don't really have the right gear for a T28, they'd barely even be able to handle a T25.

if you want to feel a large difference in power but not actually have such a massive amount of boost running, then i suggest that you get all the fuel gear from a laser and just try to find a td03 (16g) turbo for cheap and run it on 8psi for daily use and 12psi for racing, the engine should handle it fine.

also, if you turbo the car, don't forget that you need a turbo timer and a boost controller so that you never forget to cool your turbo down and you never **** up and run your boost to high.
__________________



If i still owned an excel.. It'd look like this:

HyundaGuy is offline   Reply With Quote
Old 01-26-2006, 05:26 PM   #4
Bino
Written Off
 
Join Date: Mar 2005
Location: Phoenix, Oregon, USA
Posts: 844
Most factory N/A motors aren't very happy on much more than 5-7psi of boost on stock internals. Although I don't have first hand experience with the Miata specificially, this is the amount of boost typically run through the Honda K-Series and the Dodge 420A when a turbo system is bolted up (I'm sure there are thousands of people than run much more boost than that, but for reliability most people run 5-7psi). 12psi is what a factory turbo Eclipse (i.e. lower compression ratio) runs stock.
__________________
Build 'em Light and Wind 'em Tight.
Bino is offline   Reply With Quote
Old 01-27-2006, 03:01 PM   #5
Golddragoner
CF Enthusiast
 
Join Date: Jan 2006
Posts: 244
Its not the fact that a stock turbo car can run 12psi...stock non-turbo cars have the wrong pistons in them to run turbos at a high PSI. These cars have much too high of a compression ratio (I know for the D16A CRX engine the stock pistons are 10.5:1 while a turbo needs 9.5:1 to work at PSI's higher than 8 or so). The best way to go if you have the money is to get forged pistons with lower compression ratios and eagle rods.
Golddragoner is offline   Reply With Quote
Old 01-27-2006, 05:57 PM   #6
Bino
Written Off
 
Join Date: Mar 2005
Location: Phoenix, Oregon, USA
Posts: 844
Quote:
Originally Posted by Golddragoner
Its not the fact that a stock turbo car can run 12psi...

Yes, in fact, it IS that a factory turbo car will run 12psi reliably on lower compression ratio pistons. You clown.
__________________
Build 'em Light and Wind 'em Tight.
Bino is offline   Reply With Quote
Old 01-28-2006, 12:54 AM   #7
OombaIsBack
Banned
 
Join Date: Jan 2006
Posts: 285
I'd stay below 10 lbs until you do a rebuild
OombaIsBack is offline   Reply With Quote
Old 01-28-2006, 05:23 AM   #8
HyundaGuy
Relicensed n ready 2 race
 
HyundaGuy's Avatar
 
Join Date: Jul 2005
Location: Adelaide, SA, Australia
Posts: 674
Quote:
Originally Posted by OombaIsBack
I'd stay below 10 lbs until you do a rebuild


for the first time in... well... ever! i agree with oomba.
__________________



If i still owned an excel.. It'd look like this:

HyundaGuy is offline   Reply With Quote
Old 01-28-2006, 10:55 AM   #9
Wally
I Know More Than You
 
Wally's Avatar
 
Join Date: May 2004
Location: Oz
Posts: 2,564
Quote:
Originally Posted by Golddragoner
Its not the fact that a stock turbo car can run 12psi...stock non-turbo cars have the wrong pistons in them to run turbos at a high PSI. These cars have much too high of a compression ratio (I know for the D16A CRX engine the stock pistons are 10.5:1 while a turbo needs 9.5:1 to work at PSI's higher than 8 or so). The best way to go if you have the money is to get forged pistons with lower compression ratios and eagle rods.

Gee I wish I could pull figures out of my hat like that.

I would have thought you would be fairly safe pushing 12 psi on standard pistons, however getting the lamda down to around 0.8 would be advisable (read you need an aftermarket ECU, sized injectors, etc). The compression ratio should be applied to your valve events and rod/stroke to get a dynamic ratio. The dynamic ratio should be about a point lower than recommended for aesthmatic engines for the fuel you are using.

Molded hypereutectic or semi forged pistons are quite suitable for a decent amount of abuse. But standard mold jobbies can also handle a lot. Whether the pins and bearings can hold up to extra stress without throwing a leg out of bed, is another matter altogether.
__________________
"She gave me a look only a mother could give a child."
Wally is offline   Reply With Quote
Old 01-31-2006, 11:19 AM   #10
HyundaGuy
Relicensed n ready 2 race
 
HyundaGuy's Avatar
 
Join Date: Jul 2005
Location: Adelaide, SA, Australia
Posts: 674
Quote:
Originally Posted by Wally
Gee I wish I could pull figures out of my hat like that.

I would have thought you would be fairly safe pushing 12 psi on standard pistons, however getting the lamda down to around 0.8 would be advisable (read you need an aftermarket ECU, sized injectors, etc). The compression ratio should be applied to your valve events and rod/stroke to get a dynamic ratio. The dynamic ratio should be about a point lower than recommended for aesthmatic engines for the fuel you are using.

Molded hypereutectic or semi forged pistons are quite suitable for a decent amount of abuse. But standard mold jobbies can also handle a lot. Whether the pins and bearings can hold up to extra stress without throwing a leg out of bed, is another matter altogether.

true, i do agree with you about 99.5% there, but depending on the turbo and also the c/r of the vehicle itself depends on the boost you can run, i mean you can't really push 12psi on a vehicle with a 13.5:1 c/r can ya? lol.

do you think you'd be able to explain why the c/r needs to be lower to handle higher boost in a detailed content? cheers wally, you're a legend.
__________________



If i still owned an excel.. It'd look like this:

HyundaGuy is offline   Reply With Quote
Old 01-31-2006, 05:36 PM   #11
Bino
Written Off
 
Join Date: Mar 2005
Location: Phoenix, Oregon, USA
Posts: 844
Quote:
Originally Posted by HyundaGuy
true, i do agree with you about 99.5% there, but depending on the turbo and also the c/r of the vehicle itself depends on the boost you can run, i mean you can't really push 12psi on a vehicle with a 13.5:1 c/r can ya? lol.

do you think you'd be able to explain why the c/r needs to be lower to handle higher boost in a detailed content? cheers wally, you're a legend.

Yeah, ya can... actually. You're only battling the octane rating of the fuel. We ran a 12:1 CR motor up to 18psi on Methanol (it was a Kawasaki Ninja). No detonation whatsoever.
__________________
Build 'em Light and Wind 'em Tight.
Bino is offline   Reply With Quote
Old 01-31-2006, 07:33 PM   #12
newyorker
MXman
 
newyorker's Avatar
 
Join Date: Nov 2005
Location: Philly
Posts: 5,291
I know that on my car, the stock setup handles 7PSi, and then you gotta change things. Ive even read somewhere that my motor handles up to 600 horsepower (the block) but im not sure. I would go with vlc on this one
__________________
04 Mazdaspeed Miata #2373/4000: IHI, BBS, Harddog, Flyin'Miata.

newyorker is offline   Reply With Quote
Old 02-01-2006, 05:22 AM   #13
HyundaGuy
Relicensed n ready 2 race
 
HyundaGuy's Avatar
 
Join Date: Jul 2005
Location: Adelaide, SA, Australia
Posts: 674
Quote:
Originally Posted by Bino
Yeah, ya can... actually. You're only battling the octane rating of the fuel. We ran a 12:1 CR motor up to 18psi on Methanol (it was a Kawasaki Ninja). No detonation whatsoever.

damn, 12:1 CR with 18lb of boost! **** me dead, that's definately an acheivement!. (that's not sarcasm).
__________________



If i still owned an excel.. It'd look like this:

HyundaGuy is offline   Reply With Quote
Old 02-03-2006, 05:28 AM   #14
Golddragoner
CF Enthusiast
 
Join Date: Jan 2006
Posts: 244
Quote:
Originally Posted by Bino
Yes, in fact, it IS that a factory turbo car will run 12psi reliably on lower compression ratio pistons. You clown.

ummm isn't that what I said? that non-turbo cars have too high of a compression ratio to run high turbo PSI? I swear that I said that...


And 18PSI on a stock engine? that I find very hard to belive unless the engine happened to be built for a turbo on it...no way could you put 18PSI on a stock engine, you'd blow out the head gaskets and seriously screw up the crank even bending the rods because of too much compression (it'd be like a diesel engine, blowing up before it hits Top Dead Center putting a hell of a lot of force on the components)
Golddragoner is offline   Reply With Quote
Old 02-03-2006, 05:54 PM   #15
Bino
Written Off
 
Join Date: Mar 2005
Location: Phoenix, Oregon, USA
Posts: 844
Quote:
Originally Posted by Golddragoner
ummm isn't that what I said? that non-turbo cars have too high of a compression ratio to run high turbo PSI? I swear that I said that...


And 18PSI on a stock engine? that I find very hard to belive unless the engine happened to be built for a turbo on it...no way could you put 18PSI on a stock engine, you'd blow out the head gaskets and seriously screw up the crank even bending the rods because of too much compression (it'd be like a diesel engine, blowing up before it hits Top Dead Center putting a hell of a lot of force on the components)

I'm sorry it's outside your realm of belief. Sport bikes have very efficient combustion chambers and are dramatically overbuilt.
__________________
Build 'em Light and Wind 'em Tight.
Bino is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Forum Jump



All times are GMT +1. The time now is 02:16 AM.

Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright 2002 - 2011 Car Forums. All rights reserved.