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Experience with Holley Dominator SBO Manifold under Boost?
Hello,
I currently run a 76 SBO with .055 milled #8 heads (heat risers poured with aluminium), stock internals (rings filed open), upgraded with a mild XE262H comp cam, stiffer valve springs and an Edelbrock performer dual plane intake.
Fueling is done by a 600hp poweradder FiTech unit that is blown through by a "GT45" ebay turbo via a Pro Charger carb hat (picture still shows the Spectre hat).
The engine is backed by a Powerglide with a 3000 Stall B&M holeshot and this is used to power a 1750lb Altered with me in it. Sofar good for an 10.6 on a non prep track with 8psi of boost.
The car will get an intercooler over the winter as the intake temperature are getting way to high, found this issue thanks to the datalogging function of the FiTech.
An other idea is to let the engine breathe a little bit better with a Holley Dominator single plane intake and a Lunati Cam:
Lift: .496''/ .520'', Duration: 290 Deg / 300 Deg, LSA: 112 Deg
To me this cam looks like the Edelbrock 7112 cam as it has the same specs?
Does anyone have experience with this cam and intake under boost with throttle body EFI??
Last edited by Altered 1978 350 Olds; Nov 2, 2023 at 05:16 AM.
Very cool. What compression do you figure you are currently at, 8.6 to 1? No one speaks highly of that rpm cam but I know a lot of cams aren't currently available still. Isn't a wider LSA wanted with boost? I would think the Street Dominator has larger runners then a Performer. It has been mentioned that the Performer has smaller runners then the factory intakes. Good luck, hopefully guy with experience chime in.
You're probably better off going to a Victor intake - assuming you can find one.
Lunati has different cam lobes than Edelbrock. The closer-to-stock cams tend to have similar specs from all the manufacturers because there's only so many ways to skin that cat. The actual lobe will be different, but probably not enough to really matter. Adding 10 degrees of 0.050 duration will definitely help, but that might be as far as you can reasonably go with the rest of the combination.
With a car that light focusing on high revs might be more fruitful, especially if you run 1/4 mile. It's gotta be tough to make use of high torque off the line.
I ran a blow through set up on a 350 with the holley intake and liked it. I’ve always read that using a dual plane in a blow through set up gives poor fuel distribution, how has it worked for you?
I ran a blow through set up on a 350 with the holley intake and liked it. I’ve always read that using a dual plane in a blow through set up gives poor fuel distribution, how has it worked for you?
To be honest, I have no idea I checked the plugs after a few runs and they all looked fine. The heads were of last winter to install the stronger valve springs and all the chambers and pistons looked fine and the same on carbon build up.
I do only run full throttle or idle, hardly any partial throttle.
Maybe the use of the TB EFI might help as it does not really care on the load conditions compared to a carburator.
ps. nice set up on your engine!
Last edited by Altered 1978 350 Olds; Nov 6, 2023 at 03:01 AM.
You're probably better off going to a Victor intake - assuming you can find one.
Lunati has different cam lobes than Edelbrock. The closer-to-stock cams tend to have similar specs from all the manufacturers because there's only so many ways to skin that cat. The actual lobe will be different, but probably not enough to really matter. Adding 10 degrees of 0.050 duration will definitely help, but that might be as far as you can reasonably go with the rest of the combination.
With a car that light focusing on high revs might be more fruitful, especially if you run 1/4 mile. It's gotta be tough to make use of high torque off the line.
A Victor Intake is impossible to find here in Germany, Chevy is what everybody uses, getting across this Holley is already like winning the lottery. The Edelbrock 3711 is the one everybody uses, the 7111 or 2711 are nearly impossible to find. You can get them new but not for a reasonable price.
At all the races I have been nobody races with an Oldsmobile engine, mostly Chevy some Fords, all others are domestic brands (European like VW, Audi, BMW, Fiat, Opel etc.) and some japanese like Honda or Toyota.
I looked at both cam cards and the specs seemed the same to me, I will check if I will install the cam this winter or save it for a next engine (more projects are awaiting)
Getting off the line is going quite ok sofar, I start with a 2500-to-3000rpm on the 2 step/transbrake, depending on the track, then the boost is also not so high (2-3 psi) and then let her ripp.
The 14x31 Hoosiers are doing a fine job sofar, some wheelspin is there and the car is fishtailing a bit but it's steadily moving forward and not going up in smoke.
Just for the information, these tracks are small airfields that are bare virgin tarmac, no rubber, no glue and traction compound is not allowed to be used. Only a small rolling burn out.
Future plans are a progressive boost controller and a programmable timing control (both time based).
Last edited by Altered 1978 350 Olds; Nov 6, 2023 at 03:07 AM.
Very cool. What compression do you figure you are currently at, 8.6 to 1? No one speaks highly of that rpm cam but I know a lot of cams aren't currently available still. Isn't a wider LSA wanted with boost? I would think the Street Dominator has larger runners then a Performer. It has been mentioned that the Performer has smaller runners then the factory intakes. Good luck, hopefully guy with experience chime in.
The compression ratio in stock from is about 8.5:1. The milled heads should bring me in the to about 9:1.
The only reason why I milled the heads was because the Comp cams base circle was to smaller then the stock cam and it would require longer pushrods, Milling the heads corrected the pre load on the lifters and valve train geometry.
The increase in CR was a bonus. It was also the cheapest solution to solve the problem
The LSA could be higher with boost but after watching several videos from Richard Holdner (and others) on cams vs boost I do not think it will make that much of a difference #wrong cam.
For me boost (from a turbo) ist just a multiplier of the engine output. Make it work fine in naturally aspirated form with a reasonable compression ratio depending on the fuel you use and then add a turbocharger.
250hp naturally aspirated will result in 500hp with 14,5psi from a turbo.
If the boost or the CR is getting to high I will change to E85 or E100 for fuel, at this moment I use Aral Ultimate 102 octane from the gas station here in Germany.
Ethanol fuel has an other benefit as it is an oxiginated fuel, just as methanol or nitro, resulting in more power, only from the fuel change.
Ethanol based fuel also has an higher octane rating, which means more timing can be used, again resulting in more power.
Last edited by Altered 1978 350 Olds; Nov 6, 2023 at 05:32 AM.
Reason: Wrong fuel brand
Not really. 100 octane is 100 octane, with or without ethanol. However if the fuel has more oxygen in it that could be beneficial.
On the 100 is 100 you are right. As mentioned before, the ethanol carries oxigin in the fuel itself which is benificial
I may have written this not specific enough, I meant that E85 that I can get in France at the gas station is about 100, the Shell V power is 100 and the Aral Ultimate has 102.
Compared to the normal fuels availabe here which are about 95 or 98 oktane the E85 has a benefit.
The E85 is also a cost effective alternative to the Shell and Aral fuels as it is about 0,90€ compared to 2,20€ per liter and still has the same octane rating.
A few years ago a friend of mine build a 2.0 liter turbo OHC engine (like in the Pontiac Sunbird), resulting in 285hp on 98 oktane, switching to E85 with more timing resulted in 315hp without any other changes.
For me the octane rating and the oxygen in the fuel were the ingredients to make this possible.
Last edited by Altered 1978 350 Olds; Nov 7, 2023 at 01:07 AM.
On the 100 is 100 you are right. As mentioned, before the ethanol carries oxigin in the fuel itself which is benificial
I may have written this not specific enough, I meant that E85 that I can get in France at the gas station is about 100, the Shell V power is 100 and the Aral Ultimate has 102.
Compared to the normal fuels availabe here which are about 95 or 98 oktane the E85 has a benefit.
The E85 is also a cost effective alternative to the Shell and Aral fuels as it is about 0,90€ compared to 2,20€ per liter and still has the same octane rating.
A few years ago a friend of mine build a 2.0 liter turbo OHC engine (like in the Pontiac Sunbird), resulting in 285hp on 98 oktane, switching to E85 with more timing resulted in 315hp without any other changes.
For me the octane rating and the oxygen in the fuel were the ingredients to make this possible.
Yep, gotcha.
But I’ve done 2 back to backs on Gas vs E85 and never really saw a difference in timing requirements. But if it worked for him then go for it.
Yep, gotcha.
But I’ve done 2 back to backs on Gas vs E85 and never really saw a difference in timing requirements. But if it worked for him then go for it.
Interesting, were these "boosted" engines or NA? Did the gas and E85 have the same octane ratings? From my experience under boost the gains are more present then on an NA engine.
For me the E85 will be a future option, sofar I will stay with the high octane gasoline from the regular gas station.
Main reason is that the FiTech 600 power adder unit that is currently used is not capable of supporting the power level with E85 due to the additional fuel that is needed (about 30%).
600HP on gas will only support about 420HP on E85. That means I would need to get the 1200HP Power Adder unit to support 840hp on E85.
I checked the plugs after a few runs and they all looked fine. The heads were of last winter to install the stronger valve springs and all the chambers and pistons looked fine and the same on carbon build up.
#wrong cam.
