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Discussion Starter · #1 · (Edited)
Im not very familiar with nitrous, but im trying to learn here. My good friend has a 84 thunderbird with a windsor engine. Year before last the car had a 410 inch stock block engine with a pair of ported high ports. The heads had a 2.10 intake valve. The portwork was clean looking but the heads were small. They flowed [email protected], and had a min csa at the pushrod area of 2.28". It was a high compression engine, with a solid roller. (we didnt ever find out what camshaft it had because he sold the shortblock at the end of the season.) It had a standard super vic intake with a great working carb shop 950cfm 4150 carb. It had a 4200 converter (unknown origin....supposedly a nitrous converter of some kind). 3.90 gear and 28x10x15 slicks. Car would run 10.67 on hp, and eventually ran [email protected] in the eighth on n20, (heavy nitrous in my opinion...(but im not claiming to know much) somewhere in the 400 range leaving on a progressive (plate style) It regularly saw 7700 rpm,, and we knew that the block was probably on borrowed time.
Fast forward to the next season. He then purchased a Dart block, 430 cube deal with 13-1 compression, and a pretty healthy sized solid roller. 276/[email protected], .780/.770 on a 115lsa. He added a dominator carb, which may have ultimately been a bad choice since the 4150 worked so well the year before. He had the heads professionally worked over. We also got a victor glidden intake that had a bit of work done to it. The heads now carried a 2.6" cross section at their smallest point, and flowed [email protected], and 335 @.700. We were told the heads would be more n2o friendly than before. Airspeed slowed down and more condusive to moving a dense mixture. The cyl. head guy recommended spraying no more than 400hp worth of n20 as the engine was large, and although the heads were better, they were still small on 430 cubes ultimately. My friend didnt really buy into it.....as he says "so what if the majority of the gain is in the first 400.......if i can pick up a tenth with another 150, im gonna try." I myself, am not really sure it works that way, but that's why i'm here. He got a new bolt together converter for the glide, and had it built for 600 worth of nitrous alone. It was built to get 3500. VERRRRRY TIGHT in comparison.

first pass with a 73/82 big shot tune only went 6.40
second pass pilled to make 275 went 5.98
they made a couple passes on both kits totaling about 525 and it only went 5.70 flat which barely beat the best of their prior year.

They abandoned it for the rest of the year due to family health issues.....

I have a different friend that has a similar shortblock and overall race weight. It is about the same cubes and compression, has a vic jr head that with a 2.08 valve flows low 330s. super vic ported. similar solid roller and all. It went 5.44, and 8.66 on a single plate kit jetted for 350. Can anyone point out the most major issue that need addressed? Any similar combinations that ran well that we could learn from? Thankyou.....were hoping to figure it out this season when he gets back from vacation. I appreciate the expertise on this page.
 

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sounds like your lugging the motor with the tight converter, sounds like he needs to slow down and learn what the motors telling him with reading the plugs bet the 60 ft sucks
 

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Discussion Starter · #3 ·
sounds like your lugging the motor with the tight converter, sounds like he needs to slow down and learn what the motors telling him with reading the plugs bet the 60 ft sucks
I'd agree with the lugging the engine statement. It hangs on the converter forever it seems. Doesn't shift high until probably 450 feet.
 

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Discussion Starter · #5 ·
It is almost 3400 at race weight. I'm sure it would go 6.25-30 on motor with the right gear and converter. But it's severely lacking when sprayed. Converter seems super tight as well
 

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Discussion Starter · #6 ·
It is almost 3400 at race weight. I'm sure it would go 6.25-30 on motor with the right gear and converter. But it's severely lacking when sprayed. Converter seems super tight as well
I was really hoping some people would comment on induction..... And how much nitrous is unreasonable when the induction is only "so much to work with". I feel 600 worth of nitrous is kind of ridiculous when you have a port that is area limited even on motor only.
 

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Discussion Starter · #8 ·
Let me ask you this........ With the induction that we have available...... What is the most nitrous you can see being effective on 430 cubic inches, with a port of that size?
 

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500 shot shouldnt be a problem but its the whole combo that can dictate the max ,the converter is stalling to low to use the cubes and nitrous available even with the first combo you had the converter was prob to tight and when using a glide the converter needs to be spot on to work
 

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Discussion Starter · #15 ·
back when it was N/A it was 590 hp but that was a whole differant combo
Ok...... Maybe I'm missing something.... But even with a nitrous cam, different quench, or whatever comes with it.....I feel like it still has to make alot more than 486, right? I can't help but think that if you're doing 500 at something, and the end result is only 350 extra, then it's probably not an efficient engine for that amount of spray..... Is that the wrong line of thinking? Last year he had 125 less nitrous on the car, and yet it ran the same et as now. But it did have a looser converter.
 

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Discussion Starter · #16 ·
cam events change the way it will run N/A if cam it ground for alot of nitrous
I can agree with that, but on the other hand, we have had some NA engines that people would swear had nitrous grinds, that worked quite well on hp. Proper gear and converter make up for a multitude of split and wide lsa.

The last strong 406 we had was 283/301 on 114, .860/.811. Most would call that a nitrous cam. Made 801 at 7500 with no vac pump, and ported dart pro 1 230 heads....(serious heads) andwas still climbing. Owner opted to stop the pull early because he was only hoping for 780. Motor was expected to peak at 7900-8000.
 

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im telling you fix the converter and it will fly ,we ran our vega N/A once with the nitrous combo and ran a 9.95 it was lazy as hell because the converter was setup for nitrous
 

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Discussion Starter · #18 ·
im telling you fix the converter and it will fly ,we ran our vega N/A once with the nitrous combo and ran a 9.95 it was lazy as hell because the converter was setup for nitrous
Okay. That sounds like a plan. How loose would you go? ?
 
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