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Old 09-06-2004, 09:59 PM   #1
preeman80
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I got my hands on some dough and a turbo and intercooler.

and now? :?

guys I need your help.. I need to know if this can work.. a friend of mine is working on his celica GT4, so he has 2 engines 2 turbos and 3 intercoolers.. he is takig the intercooler to replace his stock.. he has a bigger turbo and a high flow turbo as well.. so he is offering me his stock CT-26 twin entry turbo (I know these also worked on the MR2) and his top mount intercooler..

Since he is doing his custom manifold and custom exhaust and custom piping for his new front mount intercooler.. we can both do our stuff together thus cheaper...

Now.. Can this work? a CT-26 twin entry turbo on my SP20? possible? I am happy to run a low boost if need be. Just get the things in.. and when I do have the money upgrade everything..

I am thinking I can get away with a piggy back computer?, a new fuel pump? new exhaust?

and the custom manifold, piping etc is expected... thoughts?
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Old 09-06-2004, 10:15 PM   #2
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Also, since this is twin entry... can some one tell me what order the engine fires in, as the manifold will have to be designed so that the gases do not bust against each other...
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Old 09-06-2004, 10:25 PM   #3
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That turbo would go fine on your car. Pretty sure the firing order is
1-3-4-2 just check you dizzy cap and follow the order from 1. So
will be ok to have 1&2 and 3&4 firing into 1 opening. I personally wouldn't
use the top mount cooler even a supra cooler for $150 would be heaps
better.

Best of Luck

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Old 09-06-2004, 10:32 PM   #4
preeman80
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Thanks Mal!

Remember guys.. I know nothing.. :shock: so help a brotha out.. 8)
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Old 10-06-2004, 08:47 AM   #5
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Good too see someone else daring to delve into the unknown.

Computer wise, you may be able to get away with somthing simple like an Apexi AFC or a unichip. Your fuel setup should be sufficient for low boost apps. I would talk to Wiredone as he knows sp20 inside out with respect to forced induction applications. The kit they sold originally came with a Haltech F10 but I believe they had problems with it and opted for the E6X.

IIRC the SP20 doesnt use a dizzy and has a coil setup which is electronically controlled by the ECU. This may be an issue as you will want some control over your ignition timing.
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Old 10-06-2004, 12:04 PM   #6
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I will talk to Wiredone see if I can get some help, maybe TDK can give me some tips.

Also things that popped up,
Decompressing my engine? a metal head gasket?
A seperate screamer pipe? a bit illegal i hear? for atomsphere anyway?

Piggy back computer or a SAFC & AVCR? WTF? :shock:

How do I run really low boost (try not blow my engine straight out.. maybe later)

hmm.. guys throw questions at me so i can ask around.. thanks..
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Old 10-06-2004, 12:57 PM   #7
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Decompression is acheived with a head gasket or new pistons.

Screamer pipes are highly illegal and you will get raped by the EPA. Big big fines.

Does the turbo have an internal wastegate?
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Old 10-06-2004, 01:10 PM   #8
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I think so. check this out..



its the one on the right.. I am assuming? (some insights please) that the twin exists on the left of the spool(?) are the waste gates.

"The wastegate even has 2 ports which lets the gas out still in a smoother pattern. This design offers faster spoolup, higher max HP capability, and prevents cracking."
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Old 10-06-2004, 01:19 PM   #9
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Thats the ones.
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Old 10-06-2004, 08:46 PM   #10
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Thoughts:

1. Why do I have to de-compress my engine, I was checking through Flyin Protege trubo kit install instruction, I didn't see them do anything to the engine block.. just bolt ons. Same with hi-boost. Or did I miss something?

2. decompressed engine = lack of performance when below turbo range?
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Old 10-06-2004, 09:02 PM   #11
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The higher the compression the less air/boost can be injected into the chamber before the
pressure becomes so great that you get detonation where ig ignites from pressure not spark.
lowering the compression means you can add more air/fuel before that detonation pressure
is reached and more boost=air/fuel the bigger th bang and the more horsepower.

Regards

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Old 10-06-2004, 09:38 PM   #12
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if you only run a max off 8psi with a front mount intercooler you do not need to decompress it but if it runs higher you could do big damage
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Old 10-06-2004, 09:59 PM   #13
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The Flyin' Miata are going 12psi intercooled with an ignition retard unit on the BP, and higher with a link ECU.
Me I don't want to go past 6psi in the 9er with factory 8.6 to 1 comp. But I wasn't thinking of an intercooler first up and I havn't done a comp test yet to check engine condition.
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Old 10-06-2004, 10:01 PM   #14
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I have been looking around and it seems the stock is run at 7psi, how do you turn down the boost? From what I hear it is based on, if you have an external wastegate that can be controlled, since this doesn't can i not run 5psi? 3psi? etc?

Other thing that have been suggested is to do the screamer pipe as long as possible and then merge it to the main down pipe.. better performance?? true? false?

My plan so far is to gain as much tech info/questions/answer in the next 4 weeks, satisfy myself that this is gonna work. take the next 3 or 4 weeks looking for parts/places/mechanics etc, then go for all HELL!
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Old 11-06-2004, 08:44 AM   #15
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The turbo will have a minimum threshold at which it can hold boost. The wastegate is probably not big enough to vent all your exhaust gases around the exhaust turbine. If it runs 7psi stock, its probably big enough to support 7psi minimum. You can lower this by porting the wastegate(s).

Boost is controlled by the wastegate, external/internal doesnt matter. The idea is instead of exhaust flowing over the exhaust turbine, it is directed around the turbine and out the exhaust.



The more air you can vent around the turbine the less "boost" generated from the turbo system. An internal gate is only as good as its diameter and flow capacity. The screamer pipe helps reduce restriction for the gases exiting the wastegate and hence makes the whole system more efficient. If you come to canberra you will see how mine is setup.




It also helps with seperating the exhaust gases exiting the turbine compressor from the wastegate gases resulting in less restriction on the turbine which means quicker spooling and slightly higher pear power from the system.
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Old 11-06-2004, 10:47 AM   #16
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Boost in a normal setup is dictated by the wastegate actuator which gets a
vacuum/boost reading an opens the wastegate at a set boost pressure. Not
sure if you can get one that opens fully at 3psi. My stock 2" exhaust system
limited boost to 7psi you may want to try not adding a big exhaust till you see
how it performs. Whats the normal compression of your car. The MX5's can
run more boost on the earlier cars which had a lower standard compression
of 9:1 than the later models that came up to 10:1
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Old 11-06-2004, 11:04 AM   #17
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Mal: these where my thoughts... A screamer pipe is used to reduce turbulence in the exhaust 'caused by the waste-gate, the more free-flowing your exhaust is, the more boost you will naturally get out of an internally gated turbo.

So... Is it possibly to have the Turbo preet described then use a restrictive downpipe/front pipe to limit the boost? This would solve the problem and be more cost effective too (win win situation)? Basically, Instead of having a 2" dump/front pipe with a screamer; Use a 1 3/4" dump/front pipe with no screamer. Does anyone know if this would have the desired effect or not?.... (ie bring the boost down from the 7PSI std to 5PSI)?
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Old 11-06-2004, 11:28 AM   #18
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Creating backpressure in the exhaust will restrict the amount of pressure generated by the turbo. Whether that has any effect on the turbo life is another question.

Why bother with a scremear at all if you want to create backpressure... just have a common down pipe run it into a smallish pipe just before the cat and you have instant boost restrictor.

Only down side is that if you decide to increase boost later, your looking at a new dump pipe.
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Old 11-06-2004, 11:56 AM   #19
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Also, what if he where to use a FMIC just big enough to give him a couple of PSI pressure drop?....

I'm thinking of ways to backward-engineer the system to give a restrictive effect rather than a free-flowing effect....
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Old 11-06-2004, 12:10 PM   #20
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Build for the future. Paying 500-600 for a FMIC for the purpose of restriction boost is not too smart.

Wastegate and exhaust should give you all the control needed
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