# Maxed ct9 turbo?



## velardejose (Sep 9, 2004)

Hi
My lil stock e16 engine turboed engine runs great, gobs of torque and really quick response
7 psi, without intercooler
But, the power curve suddenly flattens (sotp dyno) at around 4000 rpm
No pinging, a/f ratio keeps high, just runs out of torque and boost falls a bit
Question is, maybe I need a bigger turbo?
Thanks in advance


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## wes (Apr 30, 2002)

velardejose said:


> Hi
> My lil stock e16 engine turboed engine runs great, gobs of torque and really quick response
> 7 psi, without intercooler
> But, the power curve suddenly flattens (sotp dyno) at around 4000 rpm
> ...


What is the size of the exhaust housing and what kind of manifold do you have? Also what is the exhaust setup like?


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## velardejose (Sep 9, 2004)

I would like to hear your opinion and suggestions
Thanks in advance
The housing diam, I'll measure it


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## wes (Apr 30, 2002)

The CT9 is a toyota turbo right? If so yeah what is the exhaust housing spec.? A few things could be wrong. 

If it is a really small turbo exhaust housing then yes, it will spool great but peter out up top. The turbo falling on it;s face can be somewhat helped by a few other supporting mods. 

Reducing back pressure pre and post turbo. 

Manifold design-If you have a stock exhaust manifold with a flange welded on, building a new manifold will help, even if it is a log manifold as long as the piping diameter is correct it will probably be better overall than the stocker. 

Exhaust- A larger downpipe, at least 2.5" in diameter to an exhaust that is mandrel bent that is at least the same diameter, preferrably larger. 

Turbocharger- Porting the exhaust housing by hand and/or extrude honing. This will help increase overall efficiency provided the porting is done correctly. I'd recommend the extrude honing by itself.


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## velardejose (Sep 9, 2004)

Thanks for your answer
My pic link doesnt work, Ill fix it later
Yes it is a toyota turbo, comes in the stock starlet and glanza turbo cars 1.3 l engine as much as I know
Exhaust manifold, is custom made, 1 1/4 inch prim diam, 2.5 inch downpipe and 2 inch tubing
Sparkplugs are black with light brown around the ceramic isolator
Car runs great, superb for a home made turbo I think
Thanks for your suggestions


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## velardejose (Sep 9, 2004)

Would measuring the intake side pressure vs exhaust pre turbine pressure ratio helpful?
I know for a street car it should be around 2
Race car should be 1 or less
More than 2 the turbo is too restrictive
Or is it theoretical blablabla?
Thanks in advance


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## wes (Apr 30, 2002)

Ditch the 2" exhaust and go 3". Heck run it open and see the difference! 

I still think the turbo is too small overall.


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## velardejose (Sep 9, 2004)

This the lil ct9 turbo


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## wes (Apr 30, 2002)

Man I think you will gain at least 20 WHp if you remove the cure CD! 

LMAO anyway the primaries are crush bent, this is not helping matters any, if the exhaust and DP are crush bent this is making things worse as well.


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## velardejose (Sep 9, 2004)

I wouldnt stick one of my Rush cds in there hehehe
I know the exh manifold is the first version, but could it be the turbo is too small to begin with?
I'll remove the end silencer and let the 2 inch tubing free btw it is really quiet now
If I start an exhaust manifold project, that should include a bigger turbo, not the lil ct9
It was a great teacher, but I think I am ready for a bigger lesson
Thanks for answering


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## velardejose (Sep 9, 2004)

I removed the end silencer (no silencer at all, just a piece of 2 inch pipe)
Guess what?
Sounds quieter than my dual carbs with end silencer installed
And pushes more!
Thanks Wes


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## wes (Apr 30, 2002)

As stated, with a turbo that small the more exhaust restriction you remove the more power it will make.


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## dave_f (Dec 11, 2002)

do you have a way of measuring the intake temperature? when you push a turbo past its intended flow and pressure, it's efficiencies will drop off. A good indicator would be excess intake temperature. An intercooler might not be a bad idea in that case, though it may be a band-aide fix for an undersized turbo. The best way to determine if your turbo is too small is to look at the compressor map, in this case it may not be an option... finding a compressor map for that turbo may be impossible.
what are using for engine managment? how are controling your spark advance? timing can play a big part in the drop off in torque. do you have an EGT gauge?
-dave


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## wes (Apr 30, 2002)

dave_f said:


> do you have a way of measuring the intake temperature? when you push a turbo past its intended flow and pressure, it's efficiencies will drop off. A good indicator would be excess intake temperature. An intercooler might not be a bad idea in that case, though it may be a band-aide fix for an undersized turbo.
> -dave


Especially in his application given that it is not curently intercooled!


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## wes (Apr 30, 2002)

OK I did some research and Toyota never published compressor maps for their turbo's. From my reading I believe the turbo is too small to ever be really strong up top. If you plan on keeping the turbo then I would follow both the suggestions that Dave and I offered. 

Your next option is to switch to the CT12 which was slightly larger, although I am not sure if it uses the same flange... 

My advice is to fix the existing problem within your setup before you start switching turbo's because they will just be problems on the new setup if you don't.


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## velardejose (Sep 9, 2004)

Thanks a lot for your time
I tried pushing this config hard just before arriving home tonight
After removing the silencer the engine pushes harder and is more responsive 
At 4000 rpm the torque falls
Boost falls also, at around 4000 rpm from 7 psi to around 5.5 - 6
As I already tasted turbo power (I really love it) and plan to get a bigger turbo I will install an intercooler to see if it can help
If not it will be installed for the bigger turbo 
I will get a thermometer to measure intake temp at given rpm/psi
This gets more interesting
Options are the mentioned ct12 and the ct20
The ct26 is too big I think








Thanks again


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## velardejose (Sep 9, 2004)

Found this data about toyota turbos and aplications

http://www.melett.com/pdfs/Toyota/Toyota Applications.pdf

What do you think about a ct20 for my e16?
Or is a ct12 enough? I want more top end power, til 5 -6k?
Dburone has a T25 in his e16, and is boosting 9 psi for more than 6 months now
Management is done via carburetor, stock dist and adv curve, mechanical spark retard and reworked for boost signal holley fpr 
Thanks in advance


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## wes (Apr 30, 2002)

velardejose said:


> Found this data about toyota turbos and aplications
> 
> http://www.melett.com/pdfs/Toyota/Toyota Applications.pdf
> 
> ...


Why go through with changing the turbo when your existing supporting mods. are just going to limit the turbo upgrade? A CT12 SHOULD be enough, however it may not seem like it with a 2" exhaust. Go to a 2.5 or 3" setup and perhaps re-work that manifold.... THEN see if it is enough?


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## velardejose (Sep 9, 2004)

Ok
Got it
Plan:
1. 2.5 inch exhaust tubing
2. Work on the intake manfold
3. Intercooler
I'll keep you posted
Thanks again
My bday is tomorrow, my car is a great gift from me to me hehehe


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## dburone (Apr 2, 2004)

velardejose said:


> Found this data about toyota turbos and aplications
> 
> http://www.melett.com/pdfs/Toyota/Toyota Applications.pdf
> 
> ...


I have only 2 corrections, spark retard is contolled by an MSD BTM, a couple of months ago it was mechanical and it also worked well.
And the turbo e16s is running since December 2004 and has almost 10.000 kms runing with the turbo


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## velardejose (Sep 9, 2004)

Sorry if I wasn't clear
That line was referring to my config
I know you run an msd 6btm
Anyway Dburone, take a look at the thread about turbo vs non turbo cams
Did you advance your stock e16 camshaft?
Peace


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