Author Topic: Questions about my 20g turbo  (Read 2095 times)

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Questions about my 20g turbo
« on: April 12, 2016, 05:10:40 PM »
here is a shot of it next to a 12a.

here is a shot from the top and it has a stock td05 exhaust wheel not the typical td05h or td06 you would see. i bought this 8yrs ago and dont remember who i bought it from or why it has the small stock exhaust wheel. i am basing its a td05 on the fact that the exhaust wheel will fit in a stock 12a housing. is the td05h wheel larger and would it fit in the stock housing???

i cant say for certain because these are old pics but i think this is a straight on shot of the exhaust wheel on the 20g can you tell from this pic if the exhaust wheel has been clipped???

i sold this turbo years ago and long story short i ended up with it again because it was on the car when i got it back from larry. i sold the turbo because i didnt care for it because it felt very laggy to me, but i was running the KDM 2.25 pipe kit and modded stock intercooler with 2.25 ends. i think maybe it was the 2.25 kit that created a laggy feels to the turbo because its now running the mk1 2 peice pipes and stock intercooler and the turbo feels completely different.

i know SQR has done tons of data logging and dyno runs with various turbos and i just wanted some opinions on the realistic limits of this specific turbo with the smaller exhaust wheel. with the smaller pipes it seems like it spools much faster or i am getting a quicker response from it due to the smaller pipes which would increase its air velocity through the pipes giving it quicker throttle response. you can really feel the power just drop off when it hits its set boost pressure though and i know its partly due to the fact i haven't ported the wastegate opening yet. i would imagine that because it moves more cfm of air it would reach its boost pressure faster there for the wastegate would open sooner or would that make no difference in when the wastgate opens?

right now its just running at 12 psi because the car isn't ready to run anything higher then that just yet. ideally i would like to see it maybe 15-18 psi with just the maft and stock injectors for now. i want to get rid of the mk1 pipes because sorry the look like crap and fit even worse not to mention the go up and down in size in more then one place. i am going to redo my intercooler piping and i am going to use the same size pipe that the stock hardpipes are that pass through the core support which is 1.75 and it will be that size from the turbo all the way to the throttle body. i also want to eliminate the ovcp and reroute them like a mpi setup and loop it into the tb from the drivers side like i know other members have done.

my thoughts behind the small pipes are that no matter how big my intercooler piping is the air still has to go through the factory TB flap which is only 1.75 so why make my turbo work to fill up larger pipes. i never understood why we would make the ovcp 2.25 because that larger pipe wont move any more air but it will take more air to fill it. the hardpipes dont really create horsepower they just eliminate the swelling of the stock pipes under higher boost pressure.

do you think it would be better to experiment with this idea with just a stock turbo instead of the 20g with the smaller pipes?

 i almost want to use a stock turbo and kind of follow in the footsteps of the tainter's and thier "free mods" quest see how quick i can make the stock motor and turbo with the addition of the maft. i know that the maft is a crewed tuning tool compaired to standalone but i still want to use the stock ecu. and mine still runs the 87 system not the 88-89 and larry was able to get the car to run the 12.73 thats on your ET list with this setup and the 17c typhoon turbo. (that was the complete limit of the car because the car did not make it home after that run with 25psi and the stock fuel pump maxed out so much it was growling) but according to the list it is the fastest recorded time on a stock ecu with street tires if i remember correct.

i am not trying to make it the fastest car out there, i just want to play with some new and old ideas and see what i can come up with. it may work great or it may be a complete fail but i wont know until i try everything i want to.

any thoughts or ideas you guys have are warmly welcomed.
1984 Dodge Conquest 58,000 miles, all original.


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Re: Questions about my 20g turbo
« Reply #1 on: April 12, 2016, 09:50:16 PM »
So what the hell is your question? Hahaha

I see boost control issues in your future without an external gate.
87 Conquest Tsi: 519whp 519wtq 7.09@102--10.95@122


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Re: Questions about my 20g turbo
« Reply #2 on: April 14, 2016, 02:41:54 AM »
you know by the time i got done writing that i think i forgot my main question. lol

it actually holds 12psi better then i thought it would, i thought it would try and creep up on me but it holds at a steady 12psi.

i guess my questions are do you think the larger 2.25 pipes were what was causing a laggy feel to this turbo when i first ran it???? <---(question) mainly because it feels so different and seems like it spools at a much lower rpm. i also dont have the manifold and hot side inlet ported either, before when i had it on the car i had those two areas ported.

and if i am going to try running smaller intercooler piping would it be smarter to use a smaller stock turbo or the larger 20g wheel??? <---(question) i think the 20g would fill the pipes faster because it can move more air, BUT wouldnt that mean it would hit it boost pressure faster and the wastegate flap would open sooner??? <----(question) if the wastegate opens sooner i would think the top end power would be lost because most of the exhaust would be trying to squeeze through the wastgate hole.

1984 Dodge Conquest 58,000 miles, all original.