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Discussion Starter · #1 ·
Have a question to pose to anyone who might be able to shine information on my problem ... I built a new combo this winter which is a 355 SBC with a Vortech YSI with a cog set up and trying to push 10 lbs of boost. Heres the problem, Ive had MAJOR problems getting this thing to run - Been all around messing with the carb and jets without luck - Today I received information that my motor is too small to run a YSI and Iam wasting my time to get this thing right - I call Vortech and they tell me that I only need 45 HP to turn a YSI. Does anyone think or know any information that the motor is NOT big enough for this blower??? I appreciate any replies. Thank You.
Patty
 

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I'm not sure on the specifics, but I know that I successfully ran a YSi trim blower on a 396ci LT1 in a full-weight street car with a cog setup at 23psi without any trouble whatsoever. Motor made 1,024hp.

Not that there is a lot to compare here, but I had no troubles.
 

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I dont think your engine is too small at all, there are NMRA renegade cars running 306 cid engines with that blower, heck there are even mod motors that use that same thing, and they are usually 281 CID
 

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Discussion Starter · #6 ·
I have a 72 tooth bottom cog and 30T on the top with a 750 blow thru - does anyone think that maybe the blower isnt spinning fast enough thats why its not working correctly?
 

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I have a 72 tooth bottom cog and 30T on the top with a 750 blow thru - does anyone think that maybe the blower isnt spinning fast enough thats why its not working correctly?
What kind of RPM are you turning?

I run a 77 & 30 on my YSI with a 302 based 371ci SBF. I make about 23#s. It made 1033hp on a stingy engine dyno. It also made 865 to the tire on a really safe tune with a 10.5 A/F ratio. My carb is an 830hp Holley that Kevin @ CSU converted. I run a hydro roller cam and shift @ 7100, the only ET I have so far is listed in my sig.
Hope this is somewhat of a help.
Aaron
 

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Discussion Starter · #10 ·
who's blowthrough carb is it?? call CSU carb's


It is a 750 CSU Blow Thru - I've talked with Kevin several times - Iam at a loss with this thing - In reading the replies I am wondering if the bottom cog is too small to spin the blower - what do you guys think?
 

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It is a 750 CSU Blow Thru - I've talked with Kevin several times - Iam at a loss with this thing - In reading the replies I am wondering if the bottom cog is too small to spin the blower - what do you guys think?
Again what RPM are you turning? IMO you are under spinning your blower but why do you only want #10s? If that is the case you might better off with something like an S-trim.
What are your goals with the combo? HP goals? When you say you are @ a loss and can't get it to run do you mean run like idle or run as in good numbers @ the track?
What is the rest of the combo? Cam specs, heads, etc.
 

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Tony McKellar
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I wasnt loosing that much boost,but I knew I was down on power....started inspecting things and found a bad o-ring in the blow off valve.Replaced it and ran the best number first pass back out.
 

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timing put some in it...Blow thrus like damn near stock timing..I ran 30 degrees with my YSI non intercooled pumping 28psi thru my 347 made 1200 hp..On C16 of course..
 

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patty i told ya the motor is fine you need to work on the damm carb thing.. or throw it in the garbage and fuel inj it. ..:)
 

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Discussion Starter · #16 ·
Again what RPM are you turning? IMO you are under spinning your blower but why do you only want #10s? If that is the case you might better off with something like an S-trim.
What are your goals with the combo? HP goals? When you say you are @ a loss and can't get it to run do you mean run like idle or run as in good numbers @ the track?
What is the rest of the combo? Cam specs, heads, etc.

Info for RPM I believe would be around 7000 to 7500 - This is new combo - I bought the YSI and short block seperately - - I figured that 10lbs of boost would be a very safe tune for running car on street as well as at the track - The block is a factory but short filled for strength. When I say Iam at a loss here is the problem - Idle is fine, when you first accelerate it starts surging and you have to feather the throttle to keep running - at 3500/4000 RPM she wakes up and wants to plant you in the seat, then at 6000 RPM it pops and finally dies out completely. The LM1 readings are all over the place from 10.4 to 15.6 to 20 then down again - Cant get the thing to WOT long enough to get good reading - - I havent had it at the track to tune on it, been doing all the tuning on the "street" because I cant even get the tires to spin for a burn out. The heads Iam running are Brodix Track 1 - - Cam is 2nd St custom cam.
 

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What is your timing @? I run mine locked out @ 27degress all the time. I run the 27 on the street with pump gas and then the same 27 with the C16 @ the track. As someone said above the B/T set-ups love timing my 27 degrees is mighty low but that is what my motor likes.
What are Kevin's thoughts on this? He has always been a great me to me on any issues I have had.
I did have an issue in the past when going from idle to a very slight throttle. I had to open the transistion slots a touch. I would give Kevin a call and go throught it all with him, he should be able to help you out.
 

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Your motor is plenty big enough for that blower as long as youre looking to make 650+ horsepower. Everything you are describing simply sounds like a carb tuning problem. What has Kevin been saying? What is your fuel system comprised of? Also... if you would please, who in the world at Vortech told you that the YSi only takes 45 hp to turn? And when they told you that did they give information connecting that shaft power to a specific blower speed on a certain engine combo? Just to clarify...yes at some speed it will only take 45hp to turn it but as the blower speed and mass flow continue to rise...so does the shaft power to turn it.

~R
 

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Discussion Starter · #19 ·
My timing is locked at 36 degrees - I do have a MAP sensor also and the MSD Programmable Digitial 7 Plus box and I initally set to pull 1/2 degree of timing per lb of boost, but did set to pull nothing out while working on tune problems. I have 112 octane fuel that I've been trying to tune car with, but the drum of 116 is sitting there when its ready to go. Iam running a MagnaFuel ProStar 500 pump with boost referenced MagnaFuel large port regulator. Kevin has told me several things to try - Its very frustrating to keep making alot of changes without any results though, and was even suggested by Kevin that I might possibly need a bigger tooth crank pulley. Kevin also suggested moving the timing to 40 degrees without any pull out but Iam a little leary about that.

When I telephoned Vortech I spoke to a guy in the "tech" department and thats who stated the 45 HP to run the YSI. The guy was given all the specs of my motor, engine size, heads, cam, carb, etc. and told me that it should not be a problem to run with the 72 tooth crank pulley and the 30T on the top.
 

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How is the fuel pressure with that regulator? Almost everyone is using a Aeromotive 13202 with success. Im just wondering if that could be part of the issue...
 
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