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Getting close to completion of my 350 Vortec build. This will be the trial engine for the management/tuning and not breaking the current trans/axle. Dart SHP 427/ProCharger will come later while this engine will go to my '69 GMC truck.
This is on my 86 Trans-Am. Currently running the stock 305 LB9 with 22 lb injectors, 1.6 rockers, Dyno-Don headers, custom tune, serpentine conversion,
99 350 Vortec block. Line honed, decked, hot tanked, etc.
Stock crank - .010 under.
Stock PM rods. ARP rod bolts.
Stock pistons (11cc dish).
Clevite bearings. Mains and Rods set to just over .002"
Vortec heads - surfaced, 1.600 stainless exhaust valves, stock intake valves, screw-in studs, guide-plates, clearanced for .600 lift. They are 062 castings.
Summit 12 point head bolts (ARP knock-off's).
Comp 08-301-8 Nitrous HP Cam (complete K kit with matching lifters, timing, push-rods, etc).
Comp 17001-16 Die-cast full roller rockers
I come up with about 9.7:1 running the .015" shim gasket.
First TPI manifold
Existing Dyno-Don headers, y-pipe, and full exhaust.
EBL Flash
Injector sizing? Brand recommendations that aren't garbage and come with useful offsets?
With the upgrade path to the 427/Procharger in mind - the plan is to keep the intake, headers, and EBL flash and only have to change the mechanicals. Any of those not going to hack it?
The biggest question I have is how easy/difficult is tuning going to be with this combo and EBL Flash? 7730 speed density conversion is my plan.
GD
Last edited by GeneralDisorder; 10-08-2018 at 06:42 PM.
Are you sticking with iron Vortec heads for cost reasons? Seems like there are better choices for heads.
Otherwise should be a potent build...
Yes - already had them and I have a real good relationship with my machinist. As this engine will make it's way to the truck I didn't see the advantage in spending three times the cost of doing these up. It's a budget build - stock crank, rods, and pistons, modified stock heads. etc. Comp's Camquest says 449.8 HP and 442 ft/lbs. Which is doubtful and I think exceptionally generous..... but it will haul my truck around no problem and be a reasonable starting point for tuning on the trans am. I will be plenty happy with 300 at the wheels for this little budget build. Stepping directly up to the 427 would be prohibitively expensive and needlessly destroy drive-train components.
I think its a good cam for a 600hp supercharger and high rpm 6000-7000 because it has high duration and will conserve intake charge which helps keep flow-rate demand on the blower lower. Depends how well the head flows I guess.
Maybe around 600hp from 350cid with average heads, 2-piece rear main reliably at gasoline compression ratios (12-18psi of boost on like a 9.5:1) so 500~rwhp
If the goal is to not have a supercharger and not spin a high rpm all the time, The duration is a bit high and the LSA is a bit wide. It would benefit N/A from more LSA because allowing some intake air to slip to exhaust will help clear the chamber and there are other factors involving kinetic energy of air molecules.
If the engine will be used on the 0-45mph street much of the time, the duration should come down because most street driving is done 2500-4000rpm, I would recommend around 218*/224* on 112 to 111 LSA depending if you have control over injector spray timing, because if you can spray the injector after the exhaust valve is mostly shut it will not harm economy or create fuel smell issues when using a tighter LSA like 110, especially since the duration isn't super high for street cars that spend alot of time 2500-4500.
Also the usual mention of keeping lift low lift and weaker springs. Unless the head is specifically designed to be used at high lift (most stock LS heads are NOT for example), and especially if the vehicle is intended for high mileage (150,000-250,000 miles I guess is 'high') it is best to use a lowest-lift and weakest spring approach. Whereby we minimize the stress and responsibilities of the valvetrain. It depends on the application because if you have some very nice powerfully crafted lifters and super hard pushrods and good guide/valve geometry etc... you can probably get away with more spring pressure or a higher lift for racing... that's the purpose and goal of competition when the playing field is 'level'. But some of us aren't racing, we are just driving the car around like a normal car so high lift and heavy spring loses its purpose.
1. It's close to the limit of what is generally considered easy to tune for. The intake duration of 224 is going to generate a stable idle vacuum. Yes the EBL has n-alpha which could help with that also.
2. The additional exhaust duration is like crutches for the Vortec heads. Which are widely regarded as being somewhat handicapped in the exhaust flow area. I also had the exhaust valves enlarged to further help with this.
3. I did a lot of calculations with the CamQuest software and this cam generated a nice curve and was recommended by a member here also. I was weighing high end HP against low end torque.... which as we know the TPI style intakes often generate too much of.
4. I might actually throw some NOS at it. LoL. Not that you can't do this with any cam of course, but this one is designed for that purpose. I also might try a procharger on it at some point. I will likely change the cam when it goes into the truck and may use this one for the next engine.
5. I do spin it pretty high quite a bit. I have a 3000 stall converter so it lives life mostly above 2500 rpm. I drive it like I stole it every time I get behind the wheel. It's the whole point of the car really. If I wanted to putt around I would drive a Camry. I spin the tires at every light and slide around half the corners I take.... I live 10 minutes from my shop so I have to make the most of my short commute.
Unfortunately with TPI we do not have any control over injector timing. It is not sequential injection. At least not with stock computer (or wiring). It is batch fire and all 8 injectors fire simultaneously. So there is zero possibility of timing the injectors.
The 113 LSA is because I do want a broad power band. I don't really want the narrow power band and idle quality issues associated with a tighter LSA.
The lift isn't crazy - it's. 500 / .520. I am using PAC 1218 beehive springs with 130 lb seat pressure but only 310 lb rate compared to the Comp included dual springs at 330 lb rate. As I understand it the beehives can handle the same lift with the lower rate.
I ended up using 7.000" pushrods and scorpion narrow body rockers. So far it looks nice on the engine stand. Have to order the First Intake and figure out what injectors I'm going to run....
GD
Last edited by GeneralDisorder; 02-26-2019 at 10:20 AM.
[QUOTE=GeneralDisorder;6284458] Well a couple reasons.
1. It's close to the limit of what is generally considered easy to tune for. The intake duration of 224 is going to generate a stable idle vacuum. Yes the EBL has n-alpha which could help with that also.
My carbed 224 Vortec was:
12" vac
13.7-14.3 AFR
850 RPM
Idling half hour in -9 C (!)
160° F engine temp
30° idle timing
FWIW: The 236 Vortec (aftermarket ported) was:
850 rpm
Less than 11" vacuum
13.4 afr fluctuating
950 rpm
More than 12"
13.2 afr steadier
That latest iteration had wasted cylinders with significant leakdown.
You should no problem with 224°
2. The additional exhaust duration is like crutches for the Vortec heads. Which are widely regarded as being somewhat handicapped in the exhaust flow area. I also had the exhaust valves enlarged to further help with this.
I can appreciate that but it's the excellent intake that makes the exhaust look bad isn't it? The Vortec exhaust port is no worse off than than any SBC head. In all reality it's the exhaust system that needs to be addressed with as close to zero loss result as is reasonably possible. Correctly spec'd headers and everything back. My understanding too is that the dual pattern cam profiles with the emphasis on extended exhaust duration often hurts fuel economy as the exhaust is opened sooner on the closing side thereby taking away some of the available torque.
3. I did a lot of calculations with the CamQuest software and this cam generated a nice curve and was recommended by a member here also. I was weighing high end HP against low end torque.... which as we know the TPI style intakes often generate too much of.
I'm a big fan of computer simulation. I have several programs that keep me amused and/or conflicted. That said, there's a split it seems when it comes to LSA and it's results. Personally, having gone the "traditional" route too many times, i going to make the move to a highly spec'd cam and will end up with a 108 LSA for a 355 or 106 for a 383. There's too much science behind my ignoring that any longer.
4. I might actually throw some NOS at it. LoL. Not that you can't do this with any cam of course, but this one is designed for that purpose. I also might try a procharger on it at some point. I will likely change the cam when it goes into the truck and may use this one for the next engine.
I've been conflicted there too. I'd probably be inclined to build a nitrous drag racer but a centrifugal supercharger also has it's appeal.
5. I do spin it pretty high quite a bit. I have a 3000 stall converter so it lives life mostly above 2500 rpm. I drive it like I stole it every time I get behind the wheel. It's the whole point of the car really. If I wanted to putt around I would drive a Camry. I spin the tires at every light and slide around half the corners I take.... I live 10 minutes from my shop so I have to make the most of my short commute.
Not unlike myself (when my ride is healthy to enough to abuse. I was shifting at 7000 grand on the 1-2 shift this summer. That said, I feel I may have explored the outer reaches of my valve train despite a host of very solid components. (The engine is obviously hurt now).
The 113 LSA is because I do want a broad power band. I don't really want the narrow power band and idle quality issues associated with a tighter LSA.
It's not the tighter LSA that hurts, it's the increased overlap that results if the duration is kept constant.. Next time you're messing around with your simulation program, do an analysis of the overlap of your selected cam (DynoSim is great for this as this). Then work the numbers while keeping the initial overlap in play.
I can tolerate the idle quality of the XR288HR I'm currently running. (That's 236 @ .050"). If I take that overlap value as a constant and tighten up the LSA I can reduce the duration numbers, keep a reasonable compression ratio and build plenty of torque.
The lift isn't crazy - it's. 500 / .520. I am using PAC 1218 beehive springs with 130 lb seat pressure but only 310 lb rate compared to the Comp included dual springs at 330 lb rate. As I understand it the beehives can handle the same lift with the lower rate.
I ended up using 7.000" pushrods and scorpion narrow body rockers. So far it looks nice on the engine stand. Have to order the First Intake and figure out what injectors I'm going to run....
Good looking engine.
(mine circa 2007)
Just a few insights. Not trying to be anything other than thought provoking.
That's funny - same timing pointer AND timing cover and both with Vortec heads. Great minds eh....
I had to modify the cloyes cover to use it with the factory roller cam setup. But it was easy to do.
As regards the exhaust system - I have Dyno Don headers and y-pipe, then 2.5" out to the bumper with the Flowmaster axle-back.
I'm not at all concerned about fuel economy. The extra exhaust duration is really important for forced induction to clear out the cylinder from what I understand.
With a carb it's much easier to deal with the large intake duration and overlap. With fuel injection you have to consider what it will do to the sensor readings at idle.
If nothing else GD (other than demonstrating my affinity for camshaft specs) this will pull your thread back to the top. Perhaps someone out there can contribute to your original EFI tuning query. I'm a carb guy. Lots of accessories and equipment added to help tune and datalog but not much to offer in the way of EFI.
I respect that. I like a nice simple carb setup myself sometimes. I have a couple of the newish Edelbrock AVS2 models with the annular boosters in the primary and am happy with it on my truck and mom's 56 Roadmaster. I wouldn't mind finding an 82-84 Trans Am I could do a wild carb setup on. Maybe with a 6-71 sticking out the hood. LoL
That combo will run like stock lol. Wont have much of an issue tuning that. Cam is fine, like a slightly hotter lt4 hotcam that works very well.
One of the better vortec combos i seen used a single pattern 224/224 and over .550 lift and on a 108 lsa i believe. 113 wont hurt it to much. First tpi will make the torque every where. 113 will widen power band up top some.
Ebl will be fine with a blower/427. You should have no problem controlling big injectors 80-127 lb. depending on what power you expect.
.One of the better vortec combos i seen used a single pattern 224/224 and over .550 lift and on a 108 lsa i believe.
Not to throw the "magazine" build into the mix but the above describes Vizard's cam spec contribution to something I read in Popular Hotrodding (or the like). It's one of the principal reasons I'd like to try that route (tighter LSA) depending on which direction this latest engine of mine will be going. Keep in mind though was a dyno engine with decent headers and collectors. The relatively poor performance of the Vortec exhaust ports was largely mitigated with the increased exhaust pulse tuning afforded by the overlap and free flowing exhaust system.
That combo will run like stock lol. Wont have much of an issue tuning that. Cam is fine, like a slightly hotter lt4 hotcam that works very well.
One of the better vortec combos i seen used a single pattern 224/224 and over .550 lift and on a 108 lsa i believe. 113 wont hurt it to much. First tpi will make the torque every where. 113 will widen power band up top some.
I see a lot of dyno results for the LT4 showing around 300-320 whp. So you think with this combo I'll be hitting somewhere around my goal of ~300 wheel?
I'll find out at any rate. The guys are pouring concrete for my DynoJet 424XLC2 install this coming weekend. I'm hoping to be up and running around early April.
So you think with this combo I'll be hitting somewhere around my goal of ~300 wheel?
GD
FYI: 350 Vortec, XR276HR (w/ 1.6 rr), carbed, air gap intake and a terribly poor flowing exhaust (mid length headers, single 3" to a highly restrictive muffler), auto, made 290 rwhp, 290 tq on a Dynojet. I'm certain that with the correct length collectors and open headers, tuned to suit, it would have made 10-20 more rwhp.
I would think 280-300 would be reasonable. But dynos vary. On our dyno i tune on, a L98 with afr 180’s and lt4 hot cam with tpis big mouth system made 272 whp. But i dont think the engine was in the best shape due to alot of blowby i seen. I would have guessed 300 on that combo for sure.
A tfs 195 head lt1 car made 355 thru a 6 spd on the hotcam. Auto would be closer to 330. Tpi would knock it down to 300-310 imo due to lack of rpm potential but the first being really large it may not lose as much
vortecs make power tho. That carbed vizard motor made 447. That would be higher 300’s whp
Sounds about right where I figured I would be. I do have very decent exhaust so hopefully I should be right in the neighborhood of what I expected this engine to produce.
I've been playing with the Comp CamQuest software and when I change the intake manifold type the performance changes drastically..... it's saying 363 HP @ 5500 with stock TPI manifold flowing around 500 CFM (I guessed at that). If I select 800 CFM (guessing on the First manifold?) it bumps up to 381 HP @ 5500.
Is that an accurate representation of the First manifold though? If I select the TPIS Mini-Ram at the same 800 CFM the power jumps up to 448 HP @ 6000. I don't have the First manifold as an option so I'm not really sure what would be the best choice to model it in software. It is designed like the stock TPI but it's WAY larger in every way...... anyone have thoughts on where it will land on the spectrum?
It would be inbetween lol short runner vs long but the first has good area for flow. If a tpi tends to peak in the 4500-5000 range and a mini ram peak in the 6000-6500 range, then first should be strong in the 5-6
So maybe close to 400 crank or a little more. I'm excited to see what it can do. I sent an email to Ken at First asking his experience in these matters.
Here's the spec on that 350. Engine 2007
353: 4.020” x 3.48” (late 70's 4-bolt main out of a truck/brand new purchase in '98...interesting story)
5 cc piston
Resized stock rods w/ ARP bolts
.030” deck
670 Holley
RPM Air Gap
Vortec heads. Decked .006”. 63 cc (?)
Comp XR276HR. 276/282, 224/230, 110 LSA, 106 ICL, 64 ABDC IVC
Victor Reinz 5746 head gasket .026” x 4.120”
Mid length headers
3" over the axle and Chokemaster muffler
10.05 SCR / 8.08 DCR
Cranking pressure 185-190
Best 1/4 mile results: 12.449 @ 108.551 MPH corrected
Street suspension w/ET Streets
Vehicle weight: 3700 lbs.
Unfortunately there's no RPM axis to go with this although you can see 5252 at the HP/torque crossover . Test ended at 6000. (I estimated and sketched the RPM scale in by hand)
Overall a pretty flat torque and HP curve which probably contributed to this chassis overachieving the dyno results.
Maybe this will give some insight on what to expect from your build. I expect better results from your combination.
That's just disturbingly similar to my build. Only major difference is I used the -11 cc stock Vortec piston, the .015" gasket, and my slugs are .025" in the hole. And I have the NX276HR instead of the XR276HR. And I guess the mild change I made to the exhaust valve size. And I do have a decent exhaust that shouldn't restrict any significant amount.
Wait...if that was a 70's block.... was that a hydraulic roller build or flat tappet?
I do have a Fluidmpr balancer and a melling shark pump in there.
GD
Last edited by GeneralDisorder; 02-27-2019 at 10:53 PM.
Yep. It was a never used late 70's block that an auto shop teacher had stored in his garage for 20+ years. I bought it in or around '99, sent the short block to my machine shop, had flat top hypereutectic pistons installed (5cc and .030" down the hole) and the stock rods fitted with ARP bolts. Cast crank too. Initial build was a flat tappet (Comp 268H copy) and eventually went with retro -fit hydraulic rollers and the 276HR. Added the Cloyes Hex -Adjust timing set and 2-piece cover. That more or less stock bottom end took a real beating although with power levels less than 400 chp and RPMs generally less 6200, it lasted a very very long time. The Vortecs were fitted for screw-in studs w/guide plates and Comp 26918 beehive springs.
It will be very interesting to see what the difference in dyno curves is between them. Did you have roller rockers on it with the retrofit? I had to get Scorpion narrow body rockers to fit the Vortec heads. There weren't many options that clear the center bolt valve covers.
I was running Comps 1.6 Pro Magnums at the time. That necessitated clearancing the supports in the valve cover. Didn't take much. IIRC there was some contact with the factory oil baffle as well but it was very minor and didn't present any fitment issues.
I tried the newer (less expensive) Comp aluminium body RR's and the fitment wasn't happening. So I ordered the Scorpion narrow body set as they were less expensive than any of the Comp options, USA made, excellent reviews, etc. I'm also running those taller cast aluminium valve covers in the picture so no fitment issues at all. They do have baffles for the PCV so should perform similar to stock. Hopefully blow-by will be minimal anyway since I'm running stock pistons (they were in excellent shape - not even any scuffing on the skirts after 177k) and stock cast iron rings (gapped for a little NOS perhaps).
This is the response I got from Ken at First Performance about the First Intake:
"The FIRST Tpi flows over 30 % more than the stock GM tpi. The FIRST will pull extremely hard and higher in the rpm range than the stock tpi. The mini ram will give you much higher rpm results than the FIRST tpi because it is a short runner, but the FIRST will have a ton more torque than the mini ram by far from off idle all the way up. I feel that the HP should not be far off from whatever the mini ram power will produce, but it just won’t do it at 6000 rpm like the mini ram."
So that's good information - perhaps somehow I can shove that 30% number into my software simulation somewhere.....
10-08-2018, 04:58 PM
