Basics in building an 11 sec HA car.

Jerryl

Jerryl

Tall Unvaccinated Chinese Guy
Joined
Dec 14, 2004
I wanted to post some usefull info (calculations) for the HA crowd am very comfortable with these numbers. By all means, if I missed the boat and you have some time slips that challenge the calculations, post them up. I just picked some arbitrary numbers to show the differences.
The assumptions made are that the car has a good tune, and no other constraints (DP/Header/Exh system, etc.)

A 231CID - HA car at 2.75 PR (23 PSI boost) needs a turbo that supplies:
Stock unported heads - around 36 lb/min @ 5000 RPM
Stock ported heads – around 40 lb/min @ 5000 RPM
Stock unported heads w/alky - around 46 lb/min @ 5000 RPM
Stock ported heads w/alky – around 51 lb/min @ 5000 RPM

If you changed the cam and peaked around 5400 RPM at the same PR the turbo needs to supply;
Stock unported heads - around 39 lb/min
Stock ported heads – around 44 lb/min
Stock unported heads w/alky - around 49 lb/min
Stock ported heads w/alky – around 56 lb/min

What this all means is that a HA car/Alky/Ported heads/Cam/Unlocked converter should be able to run around 11.54@115 at 2.75PR (around 23PSI).
If the set-up is run at 2.38PR (around 18PSI), it should be able to run 11.9X@111 unlocked, or 11.5@115 locked. You will need about 54 lb/min.

A true cold air system that takes the intake air from 130F to 70F seems to be worth 20WHP, and removing the inlet restriction (Grossly estimated the inlet pressure drop) seems to be worth about 15whp or 20F in the charge temps.

There are many who have proven that building an 11 sec HA car can be done.
I want to give credit to my friend John Estill since my calculator it is largely based on the work he has done many years ago.

Remember: The absolute HARDEST thing about building a fast HA car is to believe!
Hope you find this info useful in planning your next move. ;)

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Last edited:
charlief1 said:
Good post Jerryl but it might be interesting to add some E-85 info to this as well.
Click to expand...
Sorry Charlie, I have not worked on that model. :(
It should have an edge in the MAT, but not sure what "real life" numbers would look like.
 
Jerryl said:
Nah, that would be waaaaaaaaaay too easy .................... for those who know how to tune. ;)
Click to expand...
Well it's really about intellegence and knowledge. I'd almost bet that a HA guy that went into the IC stuff would be even faster since he had to learn more to make the HA work better.:p
 
I have a 56mm Turbo, stock rebuild, ported irons, cam, stock converter and e85. I am trying to run an 11.xx but I will most def need a new converter to do it. Ah and it has alky.
 
I'm learning a lot from this board, but I don't know what a lot of the posts mean. Call me dumb@$$, but i just don't know, still learning. When it says lb/min those are injectors? and what does it mean by peaking at a certain rpm, and how does the cam affect it?
 
The cam will run up to a point and die. The higher the the lift and duration it will give you more RPM if it's got the supporting parts. The injectors are rated at so many pounds. Say a 42 pound injector means that it's rated at 42 LBS, which is rated at minutes of flow.
 
natethegreat85 said:
I'm learning a lot from this board, but I don't know what a lot of the posts mean. Call me dumb@$$, but i just don't know, still learning. When it says lb/min those are injectors? and what does it mean by peaking at a certain rpm, and how does the cam affect it?
Click to expand...

The lb/min given here isn't to do with the injectors, it is a unit of measurement for the volume of air the turbo needs to supply.
 
ok, now things are starting to click in my head. this is good info jerryl! thank you, sir. now i see why we need to know what we're doing with these hot airs - looks like a lot of time, trial and error, and tuning is involved.

DCVING 6 said:
The lb/min given here isn't to do with the injectors, it is a unit of measurement for the volume of air the turbo needs to supply.
Click to expand...
Oh. well how much does a stock turbo supply and what turbo upgrades do we have to use to put out those numbers? and that is why you need bigger injectors to go with the volume of air from the turbo?

charlief1 said:
The cam will run up to a point and die. The higher the the lift and duration it will give you more RPM if it's got the supporting parts. The injectors are rated at so many pounds. Say a 42 pound injector means that it's rated at 42 LBS, which is rated at minutes of flow.
Click to expand...
Ok, I see. what supporting parts do you mean?
 
To put it in simple terms, the stock turbo flows just over 350 CFM maxed out. If you go with a TA33 then it gives yo almost double the flow if I remember right. If you want to go bigger you have to have one adapted or made for a HA system since there aren't many options out there.:(
 
charlief1 said:
To put it in simple terms, the stock turbo flows just over 350 CFM maxed out. If you go with a TA33 then it gives yo almost double the flow if I remember right. If you want to go bigger you have to have one adapted or made for a HA system since there aren't many options out there.:(
Click to expand...

I am at the point where due to my ported heads and cam the TA33C will never get me into the elevens. I need a bigger turbo and injectors. I chose to rebuild my air conditioning system instead chasing the eleven second goal. Cheaper in the long run. Brad
 
how does the bore of the engine affect this? i'm assuming it only helps to get into the 11s. bigger is better right?;)
 
natethegreat85 said:
how does the bore of the engine affect this? i'm assuming it only helps to get into the 11s. bigger is better right?;)
Click to expand...

A larger bore has a lot of benefit besides the "simple" increase in CID.
Think of it in terms of flow volume vs flow quality. Both are very important measures.

Re: "Bigger is better" . . . . . Depends on what you are talking about. Not with turbo's or tires, or injectors, or valve sizes . . . . . etc etc
In anything, it is not about “how big” but about the “balance of the system to meet a specific goal”.
 
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