First, I want to congratulate you on a job well done. You're making people think! I like that. The rest of the combination aside, I think what has most people scratching their heads is the fact that there is no head work done, which is coupled to a mild cam. What happened to 'cylinder fill trumps compression'? How can such a thing be? I'll leave this open for others to chime in. Aside from this, I have a question for you Tom: what's your average ambient engine temperature? You running it 'hot' or 'cold'? Thanks
If that's compression pressure (175/180) that's right about where I'm at, maybe a few pounds higher. Heres my unprofessional take on it.... Maybe that's the "crossover point" for iron heads VS aluminum heat wise, being aluminum can dissipate heat quicker than iron, so you can really stuff compression into the cylinder, along with the additional heat that comes from pressure, the aluminum can dissipate the additional heat, so your left with the additional pressure, which is a good thing, as long as the heads will flow it. How'd I do on my unprofessional analogy
Mark, that is engine coolant temperature. Gary, with 11.66 SCR, DCR, even with a mild cam would be well into the 9's. This is a race gas only motor.
I need to buy some actual race gas to see if it will pick up over the aviation fuel, as I've read there are additives in aviation fuel to make it more suitable for higher altitude, that hinder performance in a track car. The av gas is 100LL( low lead)
I understand it's a specialized race gas engine. I was just curious as to where he ran it temperature wise.
Aviation fuel might not like higher temperatures. You mentioned performance goes away as the engine gets hotter. That is pretty normal if the intake air also gets hotter. Wonder how much performance you would pick up with race gas, and cold air intake. Wasn't there a cowl induction set up for the 68-69. Thought Frank McIntyre had a kit for that. You have to cut a hole in the firewall though, I believe.
I have ran my best time when the car gets started up at about 150 degrees. By the time you get to the staging lanes and do your burnout you are at about 175-180 degrees engine runs best at this temp. I would assume that the heads are ported some and not bone stock. Race gas is about 8-10$ a gallon depending on where you can get it. I have read that the AV gas is different and the regular race gas is more suited for the engine at the high compression being ran. The race gas is at 110 It may look stock on the outside but I would bet it is far from it on the inside. Per Rules in the class. If anyone has noticed he ran a 1.79 60 ft time, you have to get the car out of the hole quickly to get a good time on the big end. So now you have to find the balance between the stock engine and the more race engine. The more race you make it the higher the rpm goes up, stick in some cam and you start to loose the bottom end, got to make up for that with stall and gears to get it out of the hole to get that 1.79 60 ft time. Now the HP you gained with your bigger cam will take over at the higher rpm. So if you get the engine to about 10.1 compression you may be able to run that 212 cam with premium or maybe a gallon of race gas and get the car in the 13's How about adding the SP3 and some headers to go with that 11.6 compression and of course some 110 gas. How about topping that with the alum heads. about 60 more hp
I imagine Larry was referring to your previous post where you mentioned the use of "non Ported heads and mild cam" in bold print in reference to its performance, to which can be mostly attributed to the gear and DCR, certainly not the heads and small cam. Get it back down to pump gas range and the performance would obviously fall pretty quick , not knocking the car's performance at all mind you, the number of 350's in the 12's are extremely limited ESPECIALLY hauling stock parts down the track , but I think Larry read your post the same as I did, and if that isn't the case than I apologize
The whole car is purpose built for the Pure Stock Drags. The engine is built to the rules, as is the trans, rear, suspension,etc. There are quite a few things that could be done differently for a different type of application. Thanks I will humbly say that this combo had a good deal of thought put into it to do what it does. My best friend and engine builder worked together on this, talking and bouncing ideas off each other. If any one thing in my combo was changed, I feel it would have a negative impact on how it runs. Tight converter with the 4.10 gear, lots of cylinder pressure, low rpm torque all do their job and play a major role in going 12.89 and only cracking 102mph. If this car doesn't hook, you might as well abort the run. It's magic is all done early in in the run. There isn't a bunch of porting done. A excellent valve job, yes, porting, no. Not needed in this build with iron intake and exhaust manifolds.
I just have to say that is pretty dang good. how about some 12.1 on your 350 today. Got me thinking, didn't Gessler run in the high 10's with his 455 I think he ran the same class. It goes to show though the difference between the 350 and 455 can be as small as 2 sec. running the same style class.
I wanted to leave the commentary open in my previous post that I believe this post is referring to (talking about 'you' (me) mentioning the use of 'non ported heads and mild cam' being in bold print). The DCR will be attributed to the SCR and the IVC point of the 'mild' cam, which is probably at least as high (the IVC @.006) as the OEM cams, which ranged from 71*-75* (this isn't a 'grunt' type grind profile's IVC point), but the DCR isn't everything when considering cylinder fill with VE, which would be limited with the use of exhaust manifolds and unported heads, so the DCR could be a bit higher. To use the TA 212-350 cam as an example (according to a cam card I have showing the specs on it) for a mild performance cam, it has 280*@.006 intake duration sitting at a 110* LSA; installing it at 0*/0* would give a 70* IVC point @.006, compared to the stock cam's 71*-75* (later closing means it needs higher SCR for same DCR). It's still well within race gas territory (I knew this, and wanted to let Larry know that I wasn't misunderstanding or trying to suggest that running it cooler could result in using pump gas). That out of the way, I want to get into the reasoning for my post that precipitated this response: It is often said that VE trumps DCR, as I was suggesting in my previous post, which doesn't apply to Tom's combination, and wanted to encourage discourse from others with their own thoughts as to why, rather than just immediately giving my rendition of it. Both methods will result in a similar outcome (high cylinder pressure), but using different techniques. Instead of using scavenging and high overlap and higher RPMs to pull in extra air/fuel for increased cylinder pressure, it is being done by using a higher DCR; the question (or suggestion for introspective thought) would be that: could this type of performance be achieved on pump gas at all, using aftermarket parts facilitating the aforementioned cylinder fill via scavenging for high cylinder pressures at higher RPM powerbands (which, like boost, would need more octane), when we see that an all iron engine with no head work but has high cylinder pressure due to increasing the compression ratio, would need the higher octane race fuel. It isn't intended to start a debate, but to give reason for looking at something from another angle. The advantage of using high compression and retaining the original engineering intent of the original castings would be that one would not need to spin it to 6500+ RPM to achieve good power. Obviously, this is a specialty-built engine/combination with one goal in mind, so it's not like this is doable for the average enthusiast who wants a pump gas friendly street machine. I also understand that the gearing and special suspension mods/tricks are needed for perfectly-timed hookup out of the hole in order to make these passes possible. Take that same engine and drop the compression back down to 93 octane friendly ethanol gasoline territory, change the gearing to a more streetable 3.23 or so, and you'd have a mid-13 car. Tom did a great job in showing what an all-iron Buick 350 can do with race fuel type compression and quarter-mile friendly gearing. With a 5400 RPM trap speed (and shift point), coupled with zero (or near zero) traction loss out of the hole and proper weight transfer/distribution, his combination is spot-on for optimized usage of power for his intended goals. He also showed that there is more than one way to achieve a desired goal. /thumbs up
Tom is running Pure Stock while GG ran F.A.S.T. which are two different classes. The engines are factory looking on the outside but FAST is an anything goes inside the engine class while Pure Stock is extremely limited to what you can do inside the engine. I'd bet the compression is up because going by Buick "NHRA Stock" racing class specifications that is the compression that you would get. I don't even know if you are allowed to open up the exhaust manifolds at all. All things being equal a 350 car vs. a 455 car that GG ran 10.90's in(@130 mph) would only have a 1 second difference in them. 100 cubes = 100 HP? Actually the 350 car would be easier to hook up on those bias ply's that are allowed(or maybe they allow real street radials, not drag radials, to run?) compared to the torquier 455 car. I believe the fastest 455 cars are only running low 12's, maybe high 11's in Pure Stock so Tom is around 1 second away in his class so he is right there. I imagine he could knock off a few 10ths if he would install a higher stall converter in it when he runs the drag tires. Of course his isn't the best way to have a streetable 350 but it is one way to get in the 12's. If you knock the compression back to 10:1 and install a looser converter and sticky tires your streetability comes back and you're still in the 12's on pump gas. As mentioned there are few 350's running in the 12's or faster. I'd bet it didn't run that fast the first time out. Probably took a lot of tuning and playing around to get it to hook. IMO the majority of 350 runners should be asking Tom how to set up their car. Keep up the good work Tom!
The sbb 350 responds very well to cylinder pressure no matter how you get it in there. Set one up with 13.5:1 compression with a roller cam with slightly more dur. @ .050", headers with a good exhaust system, ported heads with a ported Stage 1 intake with decent forged pistons use stock race prepped cap screw rods and run it on corn! Spin it to 6,000, should run really well as long as you can find E-85 where you drive it. Would be a good use for those AutoTec sbb 350 flat top pistons. CORN, CORN!(getting use to the new website platform but still miss the old emoticons! the brow guy would be here) Looks like a good recipe for a decent budget performance build, add a set of the new aftermarket H-beam rods with 2618 forged pistons and an SP3 intake and its ready for a multi-stage 500 shot of N02! Now we're talking 10 second or faster street drivable sbb 350! All thanks to CORN!(and N02 of coarse) Derek
Weren't you the one that was telling me No2 was cheating. I went 11.80 on a 125 shot, how much more do I need to get to 10.99 with that sp3. spray is fun
