Flow Numbers for PI, SVO, TFS 185, Ported TFS 185, TFS R, and Ported TFS R Heads

Yel2002GTAuto

Active Member
Sep 26, 2022
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Granit City, IL
So I am putting up some of my research on all 2V Heads.

Goal is to help everyone wether N/A, Boosted or any other application to help you select the best combination or improve your goals.

I have researched the depth of all the boards to find flow numbers for all common 2v applications. I did not find any flow numbers yet for PI Ported and SVO Ported heads but here is a real world comparison of almost everything available to you.


Intake # @ .28 flow testedResearch on Head specs by Type for Flow Numbers and HP Potential
Flow NumbersStock PISVO44 CC TFS44cc TFS PortedTFS RTFS R Ported
0.1515456676167
0.2102106122132131132
0.3138155172193193193
0.4153177212231234231
0.5156193133253264266
0.55159203241260271278
0.6160206236263276292
Exhaust # @ .28 flow testedResearch on Head specs by Type for Flow Numbers and HP Potential
Flow NumbersStock PISVOTFS44cc TFS PortedTFS RTFS R Ported
0.1494642625162
0.2849095100105100
0.3107119134138152188
0.4123134164188183199
0.5133140174206195206
0.55136141177209197212
0.6138143180214199219
 
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Next, I did the math on potential power N/A for all these heads above.

NOTE: This math typically doesn't cover everything like High Compression, Short runner intakes, big cams, etc.... use this as a tool as this measures head flow potential and many factors can raise or lower power numbers.

Math is as follows: (Intake max flow x .28 (measured flow as flow bench)) (results from flow bench results x .28 times the number of cylinders (8)) (calculated percentage of exhaust to intake flow by taking exhaust then divide by intake peaks) (next take results from 2nd step with number of cylinders and multiply by percent flow from exhaust/intake) This will give you estimated FWHP. I used a standard 15% to calculate for drive train loss but this will vary from manual to auto. Usually manuals are 12-15% and autos are 15-18% drive train loss. With aluminum Flywheels, 9.5 in stall converters, aluminum Drive Shafts, and lower gears rations like 373s or 410s can also help reduce drivetrain loss.

As an example, my auto has a 9.5 inch 4000 stall converter, aluminum DS, and 410 gears. I estimate this saved around 3-4% in drivetrain loss so around 13-15% range. Manuals with lighter flywheel, ds, and gears tend to be estimated in 12-14 ranges as another example.

I believe the calculations accurate plus or minus 10 percent from final numbers as noted above for CR, Intakes, cams and other power adders. Efficiency is always the key factor.

Here are the calculations below:

By Head Type and Flow #sPotential HP Calulations based on Head Flow Numbers
PI Heads Stock(160 * .28 = 44.8) (44.8 * 8 = 358.4) (138/160 = 86.25%) (358.4 * 86.25% = 309.12 FWHP) (309.12 -15% = 262.752 RWHP)
SVO Heads(206 * .28 = 57.68) (57.68 * 8 = 461.44) (143/206 = 69.41%)(461.44 * 69.41% = 320.28 FWHP) (320.28 -15% = 272.24 RWHP)
TFS 44cc Heads(236 * .28 = 66.08) (66.08 * 8 = 528.64) (180/236 = 76.27%)(528.64 * 76.64% = 405.14 FWHP) (405.14 -15% = 344.37 RWHP)
TFS 44cc 185 Ported Heads(263 * .28 = 73.64) (73.64 * 8 = 589.12) (214/263 = 81,36%)(589.12 * 81.36% = 479.30 FWHP) (479.30-15% = 407.41 RWHP)
TFS R 195 Heads(276 * .28 = 77.28) (77.28 * 8 = 618.24) (199/276 = 72.1%) (618.24 * 72.1% = 445.75FWHP) (445.75 -15% = 378.88 RWHP)
TFS R 195 Ported Heads(292 * .28 = 81.76) (81.76 * 8 = 654.08) (219/292 = 75%) (654.08 * 75% = 490FWHP) (490.56 -15% = 416.97 RWHP)
 
Couple things to note - Don't let the RWHP numbers fool you for the TFS R heads.... they can take cams up to .650 lift and need a big bore block too or .20 overbore on a 281 to fit. They would be close in stock form but have seen 58hp gains on engine dyno charts with cams going from .575 lift to .625 lift on the R heads... Stock TFS only can handle .580 lift max.

Very interesting and I plan to post some details soon on power numbers and how I think the real world results impacted vs math noted above...

Stay tuned...

Ed
 
So building a 400 + RWHP 2v NA.... how feasible is it and what it takes....

Based on Head flow numbers, blocks available and current results posted over the years, getting a 281 cu 2V modular is extremely difficult to hit 400hp NA....
This takes a high compression, full bolt ons, other Drive Train improvements, big cams, and a Short runner intake and may not be the best set up on the street.... Hitting 380rwhp is possible with a normal runner intake but takes a lot to get there as well but has a grear drivable power curve. Now that we are 4 generation engine platforms past the 2v most have stopped experimenting or trying to find the right parts to get the 2V engines to run with today's mustang engines.

Since there are soo many 2v's produced and most just throw a power added on them but there is always the crowd that like to run naturally aspirated.

So what does it truly take to hit 400hp on a street driven 2V NA and how far past this can you go.

1-set of great flowing heads - I have seen as hi as 408rwhp on 281 cu shortblock but with a high flow intake and you trade that off with TQ... I believe that setup was a carborated set up with Teskid block 11.5 to 1 CR on pump gas, Victor Jr manifold but only had about 340 tq with 408hp... not bad but I would like to have TQ over 400 as well..... Heads need to flow 260-300 cfm to get to 400 NA so a stock TFS head is needed at minimum but ported 185s or 195 Rs will get you over the hump with larger displacement...

2- larger displacement - you would need a stroker kit, 5.0 Boss FRPP block or 5.3 Boss FRPP stroker with TFS heads to get there with TQ and HP over 400 to the tires...

3-cams.... since most aftermarket parts for the 2v are based on the 281 platform, not many have ventured to see what HP you can get out of increased storke, larger Cubic Inche motors.... the heads were designed for 281 but the TFS heads outflow the capacity of the 281 or around 360-380hp tops on the stock bore... Cams for larger bores are not noted as a stage 4 cam in a 281 actually performs like a stage 1.5 na cam in a 323 stroker.... 42 cubic in increase from a 281 to the 323 5.3l needs to breath better up top but never caught up with the 2v as newer 3v and coyote platforms were much better out the factory... Knowing the parts available now you can do a 2v build from 400 to 500 if you have the time and money.... one noted 2v claimed 500 hp at the tires on a mustang dyno with a 12.5 cr on pump gas with custom ported 33cc TFS heads (Not R), fully customized build with part matched to .002 grams for internals and cams, custom profile cams, Victor Jr intake with Fuel injection set up.... I believe that is possible with the heads flowing around 280-290in and 220-230 exhaust ..... this was on a stock bore with a stroker crank so 5.1 L 301 cu engine with 12.5 cr and 4% increase in HP per 1 pt cr it was impressive...

Cams are limited on stock heads for lift to around .550 lift with PTV clearance issues.... the TFS stock heads are .580 no problem and can go further with some valve train upgrades, and the TFS R heads can go to .650..... largest cams advertised by any shop are .575 lift so custom cams can provide a nice bump in HP on the top side depending on how much you can get the heads to flow..... Think LS motors and how much power they put downn on a 5.3l engine...they have heads now that flow 390cfm.... Not sure what a max flow you can get out of a TFS ro TFS R head but 310 I would think would be feasible with stainless steel vales, upgraded guides and seats...etc... I know MHS and Fox Lake have some products that would hit those numbers but for a cost...

4-Compression- how far can you take the 2v in compression ratio?... Well I know that 11.5 to 1 on a custom tune can bang all day long without issue...most think old school around 10 to 1 but since these cars don't have iron heads and everything is aluminum, along with all improved cooling systems in today's standards... 12.1 I think is safe... as noted above on the 500hp na set up it was 12.5 to 1... I don't know if the car had any issues on pump gas with detonation but would need more info on pushing that far... Technology today for Ford has 12.1 CR factory with VCT.... even adding and tuning superchargers with that high CR is safe as they can change the dynamic pression using VCT... awesome stuff...

So how far can you push the CR on the 2v? Well based on a lot of reasearch, around 11.6 to 11.8 to 1 CR is safe with commpression around 195 psi per piston.... that is the safe max threshold for 93pump gas...


With all the above variables in mind, here is built 2v with a 5.3l Boss FRPP block dyno chart below with 38cc TFS heads stock, stage 4 MSH cams, full exhaust, bullet intake... this car was at the threshold of 400 to the tires and tq so the added Cubic inches caught up with the stock TFS Heads.... this was 11.3 to 1 CR.

Using this as a baseline, add in ported heads, Meizure electric Water Pump, Aluminum DS and flywheel (not sure if he had either) a PI Intake with BBK 78mm combo or try to port/extrude hone the Bullet at least (I have tried the bullet on my car and it had the same HP and TQ as the stock PI with Accufab Plenum and 75mm TB -exactly the same) I tested the BBK 78mm combo on the PI and picked up almost 10hp and 12tq over the bullet and accufab set up fyi....

Getting the CR to 11.66 to 1 would be the goal so in total, NA 420hp/tq max with the PI set up.... that would be with 2% more HP with the slight bump in compression to max things out.... with an R Head and custom cams with .610 to .625 lift you could add another 20-30hp on top of that.... Now there are a lot of 440hp TFS R headed mustangs running the Victor EFI set up but TQ dips down to the 360s and I believe you can still get to 440 with the right cam lift profile and a great port job....You don't see this much but MHS noted that is the average for their racers, so assuming NHRA class guys...

With my goal, I will be using my ported stock TFS 44cc heads, 11.66 to 1 set up with the 5.3l Boss FRPP stroker, MSH stage 4 cams... pretty much the same below except I have the drive train parts, ported heads, and Electric water pump and better intake combo....

Seeing most gains in Cubic inches or about 1.2 to 1.5 more HP per Cubic Inch... the stoker is worth 45-55 more HP and 55-65 more tq... plus the dyno chart below for my set up had PI cams (VT Stg 2.5) in the TFS heads so exhaust timing was off about 10 degress... gonna be a fun little buid as all I need now is the 5.3l short block...

Dyno Comparrison Ported TFS vs Ported PI Heads.jpg



dscf1099-jpg.jpg
 
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So looking at the 2nd dyno graph and head flow and cam numbers which had .575 lift...the stock TFS heads he was using flowed a peak of 244 cfm at .550 lift and lost flow at .600 list reverting to 236cfm ...so the stock TFS heads wasn't able to fully use the .575 lift of the cams...

With the ported TFS it still flowed well to .600 lift and would work perfectly with the stage 4 cams at .575 lift for this selection.....these flowed 263 cfm @ .600 and started to taper so .575 is probably the sweet spot....it will be interesting to see how much power potential was missed with this combo as well..... thinking 10 to 20hp is possible across the power curve...But TBD....

ED
 
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You are right to a point Nightfire....but there is a simple equation I believe....5.3 modular boss block, TFS ported heads, and MHS Stage 4 cams is the base engine needed...from a direct bolt on stand point... as you can order the engine already assembled, get the head worked from fox lake, or MHS ported/ upgraded ready to go with a 11.3 CR to 1 will put you at the door to 400rwhp...then supporting bolt ons for LT headers, under drive pullies, injectors, catback, etc... I belive the chart noted above would have hit 410hp 415tq with ported heads alone.... plus 1 factor I dont know is how much more flow the heads would flow on a larger bore...I read in some cases a bigger engine can allow for more cfm from the heads but with some larger engine heads my not gain cfm...since the 281 block shrouds these heads no one ever really tested with larger blocks......with a fully worked TFS R head.... and a custom height lift cam setup the math can go to 440 to 470 hp to the tires .... like noted above..time and money...there are thousands of 2vs that have full bolt ons with TFS heads that are just a block away from hitting 400 to the tires I belive...most of the stroker block builds I have seen on the internet have ported PI heads, too small or big of cams, and missing the main ingredients to get there...I am trying to take the guess work out and find the easiest recipe to get there.....I am just the 5.3l Short block away so once I can allocate one I will submit my findings....in the end through my auto, I believe 410 to 420 hp/tq will be the final numbers....its all about selecting matching parts and knowing how to compliment them....

NOTE: Each Point of Compression is worth roughly 4% more HP/TQ across the power curve and below are the sizes needed as examples of safe Compression selections and goals.... for example, going from a 9.6 to 11.6 to 1 compression is worth roughly 8% more HP/TQ across the entire RMP range... so if you have 320hp to the tires that is 320+8% = 346.6 or 25.6 more HP/TQ... this compound with higher HP levels too.... so if a car is making 392hp at 11.3CR and you go to 11.8CR that is 2% more HP/TQ so 393+2%=400.86 as another example.... Let say you are building a race engine running E85 or 100plus octane and go to 12.5 to 1 CR... example 393+6%= 416.58hp or 23.58 more HP..... these are just examples but I have seen 40hp and tq going from 9.1 to 1 to 11.3 to 1 on my set up as an example.... cams, intakes, timing and other components can amplify results as well...

For running 44cc TFS Heads in the 5.3l you would need an 11cc dish piston for 11.64 to 1 CR or a 12 cc dish piston for 11.48 to 1 CR... a 10cc would be 11.81. to 1 or a 13cc dish piston would be 11.32 to 1 for comparison.

For running the 38cc TFS Heads in the 5.3 you would need an 17cc for 11.64 to 1, 16cc for 11.81 to 1, 18cc for 11.48 to 1, or 19cc for 11.32 to 1 by comparison of heads and dish sizes needed....
 
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Plus, I really dont know many 400rwhp stock Short Block supercharged mustang's that haven't upgraded to better heads, block, fuel system, or had to add forged internals trying to push to 450 to 600hp from their superchargers....because they toasted their stock Engines.....cost just as much if not more in the long run....using the noted build I called out above with a blower friendly compression should give 600 to 700 safely to the tires with 14lbs of boost....our hobby is not cheap but the 2V is like the old fox body junkyard builds now...lol.... I was going to just add a blower to my car but decided to go NA again....I am already built for it and just looking to see what I can accomplish....with parts available now 400 to the tires NA would be only 2k more than the cost of a good blower combo if building from scratch ....could be lower if you find used parts or build yourself so time or money ....
 
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Plus the guys chart above that almost hit 400 rwhp ran out of flow for the cams he was using... by about 250 thousandths...head flowed great to.550 lift and lost flow to .600....ported heads flowing 20 to 25 more cfm and still gaining to .600 lift would have worked perfectly for his build...left 15 to 25 hp off the table with just matching the head flow with the cams....I have been studying head flows on all engine types and matching lifts to head flow is where most of the magic happens....having mismatch parts is what all 2v guys had previous problems with....no matter how far you port PI heads they could max out for the 281 bore if you can get to mid 230 cfm but would be too less of flow for 323 cubic inches...
 
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Adding a power added like supercharger can also cost as much to Hit 400hp especially if you are buying new and if the car is stock or not.....

Yes there are supercharger kits for 3200ish bucks.... but those alone with a pulley upgrade will not get you to 400hp...or at least not safely... for about 7k to 10k you can get a great supercharger with upgraded fuel system, intercooler, and other bolt on upgrades like headders, TB/Plenum, ect and with a conservative/safe tune push 380-440 hp on the stock bottom end depending on head unit for the SC....... it can hold up well but eventually need forged internals, cams, heads and or other work to get 500+hp... So I guestimate about 8k on the low end for RELIABLE/Safe 400hp... or about 11k for all the bells and whistles for a safe max effort on the stock Short block at 440ish rwhp...

For NA.... $6200 for a built 5.3l FRPP, $3000 for ported TFS heads, $800 for cams, $600-1200 for long tubes, and about 1k for underdrives, TB/plenum, injectors, bigger maf.... or about 11k for 400rwhp and end up with a built motor....

Anyone could build a budget build themselves but assuming someone is buying all new parts for their build it is actually pretty close......

I am just trying to show everyone the recipe for 400 rwhp NA 2vs.... can be done and be a reliable streetcar form so comparing what parts (Correct Parts to use) for this recipe. ...

If you want 500hp the forced induction is the way to go but add in at least another 3-5k for good, forged internals, head porting or new heads like TFS, blower cams....ect.... so could add on as much as anther 6-7k as you always get the bug for more boost...lol...

It is possbile NA to hit 450-500 RWHP but would need to spend about 4-5K on TFS R Heads, ported, upgraded valves, guides, springs, etc... get those puppies to flow 300 to 310cfm and you will be good... I have seen just ported TFS R heads flow 292 so getting a bit more out of them is attainable.... custom grind cam with about .625 lift and a 5.3l stroker....... Would need the Victor Jr Intake with 3160 Fuel injection set up .... Like noted above...someone claimed they hit 500rwhp on a mustang dyno with 12.5cr on stock 38 TFS Heads he ported himself... and his build has around 6k as he noted he did the himself...

Don't get me wrong, I love forced induction cars and all cars, as mine is built for 1000hp now but there is something about a naturally aspirated engines I love.... When I finish this build, I may get a new coyote mustang or do a newer car build as well within the next year or so... My wife wants a Hellcat and personally, I would rather do a retro classic mustang build to electric or find a used Tesla PLIAD for under 100k....

I love the SN95/new edge body style too much though and just want to finish the build I always wanted to do and just cruise around at car shows, and hit the 1/2 mile strip a few times during the summer... goal is 10s all motor NA 2v.... on 17x9s and MT DRs....
 
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So really pissed off today....been checking with Ford Racing for the 5.0 Boss Modular Block since last fall monthly....was scheduled for next batch by mid mar to may 2023..... contacted again today and now Mar 2024...tttt total crap... thanks to our trusted leaders who jacked up our economy and Russia for disrupting gas, oil, and iron....not sure if most of Fords metals are outsourced to European continent or is the green new deal by these elected idiots are effecting any gasoline driven car products... total crap....been trying to out source the block and none anywhere......what to do...

..
 
So good news...I found an Aluminum 5.8L GT 500 block....great price and ready to just drop in internals... I could get my teskid aluminum block reslevedd to 5.0/ 94mm bore as well through same company .... so looking into parts and items needed.....I guss it would be better to go this route to resleave the teskid or go larger to the 5.8 and get a custom cam profile .... so 8k for a modular 351 or 5k for an aluminum 323....Decision time...
 
This was a 5.3l, tfs 38cc stock heads with MHS stage 4 cams... due to displacement increase of 42 inches...the cams performed like a stage 1.5 to stage 2 cam in a 4.6l...full exhaust, 1 5/8 headders, and bullet intake which was a limiting factor...had full bolt ons like udp, cai, etc...a port job on the heads and better cam would have made over 415 to 420 I would think...search bullit mustang videos and then select more info in the name and it has the build details..

Ed
 
Good stuff. Quick question.
The Dyno sheet where you made 393hp
What was the build?
As an FYI, this wasn't my dyno sheet, this was another guy that my engine builder built from same shop and tuned by same Tuner (Pro-Dyno)... I didn't have the time or money at the time as I was moving to another military assignment then and Dave Moore built this engine... He used a lot of my testing and build to build this engine at the time.... so I have first hand knowledge and information on this build and just sharing my findings and what has worked....

Ed