Limiting the turbo for max HP on an 8V?

[Shadow]

So here's the deal. The 16v L-body project will prob not come out till next year(getting all the right parts is taking alot of time) We were looking to run an easy 10 with it, in keeping with our goal of dropping a second off our time, each year, since we started to go to the local track. Time for plan B! Now we are going to whip together an 8v from parts we have kicking around and seeing how well the last 8v went(see sig) with what was done to it, we should have no prob pulling this off. I have the whole build-up figured out but I'm waffling on the turbo. It's down to 3, all To4e wheels, a 50 trim, a 54 trim or a 57 trim. My first choise would be the 50 trim which (confusingly enough) moves the most air and also has the highest preasure ratio. Here's the rub, on an 8v that's going to need alot of preasure at less flow to overcome the inificiency of the head, do you think I would be better off running a turbo that flows less? After thinking on this for a while I had decided to go with the 57 trim which (confusingly
enough) moves the least air but can still make 444whp+ (which Gary proved) and according to Gary could have made more. Then along comes the 54, moves more air than the 57 but still less than the 50 but has a slightly lower preasure ratio than the 57. Figured I'd throw this out there, any thoughts? Thanks in advance for any input!

[tryingbe]

Run whatever gary was running.

[GLHS0658]

I believe you would want to run a turbo with more pressure (pressure wheel) to overcome the 8V head's lack of flow. So you wouldn't want to run a flow wheel into a head that doesn't flow without the pressure to "force it".

Mike

[puppet]

Here's some good reading on the subject.
http://www.mazdausa.com/MusaWeb/disp...r=introduction
FWIW you can't have flow without pressure. I'd guess picking one that will produce the most pressure efficiently ... less heat ... would be a better choice.

[Shadow]

Quote:

Originally Posted by puppet Here's some good reading on the subject. http://www.mazdausa.com/MusaWeb/disp...r=introduction FWIW you can't have flow without pressure. I'd guess picking one that will produce the most pressure efficiently ... less heat ... would be a better choice.

An interesting read, I'm pretty sure they would choose the 50 trim, which goes along with what your saying about efficient preasure. What then is the true deff of efficiency? I remember when ppl would tell me all I was going to make past 20psi on a S60 was heat, after trapping 105mph in a Daytona @ 25psi I turned it up to 26 and trapped 106, then I turned it up to 27 and trapped 107.6! This on a stock BE that's still running today.

[Shadow]

Quote:

Originally Posted by tryingbe Run whatever gary was running.

That kind of thinking is what drew me to the 57 trim.

[Shadow]

Quote:

Originally Posted by GLHS0658 I believe you would want to run a turbo with more pressure (pressure wheel) to overcome the 8V head's lack of flow. So you wouldn't want to run a flow wheel into a head that doesn't flow without the pressure to "force it". Mike

Exactly.
I've narrowed it down to these three wheels and I truly believe any one of them will do the job, just trying to decide which one will do it best.

[puppet]

Quote:

Originally Posted by Shadow An interesting read, I'm pretty sure they would choose the 50 trim, which goes along with what your saying about efficient preasure. What then is the true deff of efficiency? I remember when ppl would tell me all I was going to make past 20psi on a S60 was heat, after trapping 105mph in a Daytona @ 25psi I turned it up to 26 and trapped 106, then I turned it up to 27 and trapped 107.6! This on a stock BE that's still running today.

From my reading, efficency can be boiled down to being able to produce the greatest pressure with the least amount of heat being introduced into the air charge. So, being able to effectively cool the air charge can increase the turbo's efficency somewhat. Maybe this accounts for your success with the S60?

[Shadow]

Quote:

Originally Posted by puppet From my reading, efficency can be boiled down to being able to produce the greatest pressure with the least amount of heat being introduced into the air charge. So, being able to effectively cool the air charge can increase the turbo's efficency somewhat. Maybe this accounts for your success with the S60?

I think the way I look at it is, if I can raise the boost and detonation is not a problem, then everything must be working well.

[puppet]

heh ... kind of know what you mean. I'm using a MP+ turbo and at 26psi I expected all the usual reported problems.
... been pretty lucky so far except for that little voice telling me the Mr. turbo probably won't live long :P

[Shadow]

Quote:

Originally Posted by puppet heh ... kind of know what you mean. I'm using a MP+ turbo and at 26psi I expected all the usual reported problems. ... been pretty lucky so far except for that little voice telling me the Mr. turbo probably won't live long :P

Should really have no prob with the turbo, as long as you NEVER shut it down HOT, and as long as your running synthetic oil. I've decided to go with the 57 trim. 2 things really made up my mind. I'm going to be running a stock turbo roller cam which will limit the flow of the head at lower boost levels and a good friend reminded me....If I don't like it I can always change it later. Now we'll see if there's enough time to get it together for the 10th of June!lol

[Shadow]

Well, we didn't make it into the 10's. Hell, we didn't even beat our 11.6 from last year(that we ran with a different car)! lol Did manage to trap just over 127mph and I don't think that mph is doing the car justice as it was making way more power than the car last year. I've haven't dyno'd a car yet and I was going to dyno this one after the track closed, but I'm not going to get the chance. Also, I think the dyno would be a waist the way I'm running it right now (72lb inj's with a 52lb cal) It would show what I already know...pig rich all the way up the curve and then bam.....big HP! So this is what I'm wondering. Does anyone have enough experience with 72lb inj's and dyno plots to give a decent estimate of how much power we were making? Temp was around 70 deg, turbo is a super 57 trim To4e (flows 49lbs/min, same as a 50 trim exept higher preasure ratio) base fuel preasure was 50lb's unpluged, 72lb inj's and we were 11.8 A/F @ 7000rpm in 4th gear at 35lbs boost. I'm thinking the fuel consumtion alone with a known A/F ratio should be enough, but maybe no? If it matters, the car is 2550lbs with driver. Give it your best shot!

[Ondonti]

what fuel were you running?

[Shadow]

50/50 mix. 50% 94 pump/50% 110 race.

[Mystryguy]

PS i was talking to Gary days after they did that 444hp dyno pull and he said he wasnt running the 57 trim anymore... its been a while but im pretty sure i remember that even though i ordered the 57 anyhow