2.5 heads finally p&p and flowbench

[Ripple]

stock
intake = 194
exhaust = 169

vs.

svt
intake = 210-214
exhaust = 170

vs.

p&p
intake = 222
exhaust = 200


Not bad for my first set :) This is running with stock cams and valves. I've decided that I'm going to go with some custom stainless steel intake valves but ones not as big as the 3L valves. Brad squeezed 260/200 with the 3L valves. I think that the limitations on the 3L heads lies in the design of valves. If you compare them to the 2.5, they have are "tuplip" shaped verse the lower profile of the 2.5 valves. I won't know for sure until I get my new ones done up. The gains are good but I was a little dissappointed in gains for the intake. I think over the svt heads, there was only about 10 cfm gain overall. If anyone has flow bench numbers let me know. I'd like to see what the gain was for the svt heads across the board.


edit: added svt numbers as well for comparision that were found in this thread (http://www.fastcougar.com/forums/messageview.cfm?catid=83&threadid=55953)

[Kinger]

Actually that first set of heads was a set of dual honed SVT and stock they flowed 190 on the intake side, yours seems high for plain jane SE heads. Either way its good to know what just a P&P will net. I have 4 customers waiting for a P&P with 3L valves, and some were teetering on going with the valves but I think they will be happy they did since we can get 260+ cfm. Got any picts?

[DemonSVT]

I'd also have to agree your stock numbers are very high. Intake especially.

This also could make your after numbers higher than actual or not truely valid for a "versus" comparison.

BTW - What type/model of flow bench was used?

[Ripple]

Originally posted by: DemonSVT
I'd also have to agree your stock numbers are very high. Intake especially.

This also could make your after numbers higher than actual or not truely valid for a "versus" comparison.

BTW - What type/model of flow bench was used?

I believe that the shop uses a Superflow SF600.

check out this thread (http://www.fastcougar.com/forums/messageview.cfm?catid=83&threadid=55953) You'll see that Brad got similar numbers from the stock heads and low 200's from the svt heads prior to p&p. At first he misquoted the numbers and then posted the correct ones down the page (i think it was like the 17th post down).

[Ripple]

Originally posted by: Kinger
Actually that first set of heads was a set of dual honed SVT and stock they flowed 190 on the intake side, yours seems high for plain jane SE heads. Either way its good to know what just a P&P will net. I have 4 customers waiting for a P&P with 3L valves, and some were teetering on going with the valves but I think they will be happy they did since we can get 260+ cfm. Got any picts?

Did snap any pics because I want to finish the heads first. It's going to take about 2 maybe 3 weeks for my custom valves to be made and I would rather post pictures of the finished product.

[bnoon]

Unshroud the intake valves and there's a lot more to be had, even over our 260 CFM number. :banana:

The intake valves from the 3L are dished to increase flow at low lift = more torque at the expense of high RPM flow. Use a flat face valve for even better performance.

Kinger, just as an FYI, the after numbers will have nothing to do with them being SVT heads. Steve will take them all out to the same spec when he does the port work. SE heads can be found cheap in salvage yards and be made to flow just as well...

[Ripple]

Originally posted by: bnoon
Unshroud the intake valves and there's a lot more to be had, even over our 260 CFM number. :banana:

The intake valves from the 3L are dished to increase flow at low lift = more torque at the expense of high RPM flow. Use a flat face valve for even better performance.

Kinger, just as an FYI, the after numbers will have nothing to do with them being SVT heads. Steve will take them all out to the same spec when he does the port work. SE heads can be found cheap in salvage yards and be made to flow just as well...

Those were the 2 areas I was going to hit :) I'm getting some Manley gen 2 valves made up and hopefully that will put me up into the 250 range (since I'm going with a slightly smaller valve).

I didn't even take the dish in the 3L valves into consideration, I was just looking at the profile of valve.

[Kinger]

Originally posted by: bnoon
Kinger, just as an FYI, the after numbers will have nothing to do with them being SVT heads. Steve will take them all out to the same spec when he does the port work. SE heads can be found cheap in salvage yards and be made to flow just as well...


Yeah I was refferring to the 190 before was out of a SVT dual honed heads, the after will be same on a SVT, SE, etc. BTW Steve found a little trick and we'll probably see more then 260 ;)

[DanN]

Is somebody going to flow bench the UIMs, LIMs, t.bodys...???? Please!!

I talked to E. Hone awhile back...from the top of his head he recalled dual Honing increased UIM flow from about 155 cfu/m to about 185 cfu/m or so...If the SVT heads are flowing 210+ cfu/m then this adds some reinforcement to the idea of "triple Honing" the UIM. Its about $400 dollars and he estimated gains at about 10+ cfu/m more...SHO shop reports a 5 HP gain on the 2.5L with extra E. Hone, perhaps thats believeable? $400 is alot for 5HP but once all other bolt ons are done...3L should benefit more.

[DemonSVT]

I know my triple honing gained more (~+2.5mm) then comparing a SH UIM to a DH UIM (~+1.5mm) I'm sure the prep work I did helped and there probably isn't a "set" amount the process removes each time. I can tell you that my UIM is at the limit it can be opened up. Several secondary ports are right to some inner casting & machine humps.

Also according to SHOShop. They only open the secondaries (~1-1.5mm) in their EH UIM's they sell. They must have a special setup with EH to reverse flow the UIM from the secondary outlet ports (shorter time probably and definitely less flow) as the normal EH process (~$500 retail IIRC) in hooked into the large TB inlet and run full bore.

[FastCougar]

I think it's time for me to hone my welding skills and fab up a sheet metal UIM ;)

[DanN]

Originally posted by: DemonSVT
Also according to SHOShop. They only open the secondaries (~1-1.5mm) in their EH UIM's they sell. They must have a special setup with EH to reverse flow the UIM from the secondary outlet ports (shorter time probably and definitely less flow) as the normal EH process (~$500 retail IIRC) in hooked into the large TB inlet and run full bore.

Hey Demon (Greg), let me ask you..
Do you think it would be better to have them open the secondaries only (say 2-2.5mm) or both primary & secondary. My thinking is that (at least for me who HAS secondaries still..frown..) doing just the secondaries MAY increase the percentage flow to short runners relative to the long runners, yielding greater average velocity than if the long runners were opened up too. Basically "encourage" more short runner use....they are already bigger than primary to start, just enhance the size difference. But then again, I am only speculating..what do you think???

Either way, I would just send it directly to E. Hone, not SHO shop. Perhaps what they do is block off all the primary runners at outlet so all the flow is through secondaries???

Yeah, Ive managed to save a few bux for another mod (and me building a house..very bad) . So, maybe this or maybe a BAT suspension kit????

[DemonSVT]

I think doing both primary & secondary ports is a better option. Both runners are completely separate and each have their own valve to feed.

If you are porting the heads (even in the future) this would appear to be a must.

I can tell you the bulk of my gains are where you would expect them. 5000rpm on up. Tom (Warmonger) was impressed how well the car pulled above 5k. He said it felt as strong as his above 5500rpm. Now some of that is the fact my car is lighter than his, but being compared to a well performing 3L is quite nice IMO.

With my upcoming plans to install true duals and rework a few intake parts I expect to be even stronger up top.

Also throw some custom self programming in there :biggrin: (no more CEL!) and I'd be very upset not to surpass 200fwhp. Technically I should be awfully close as is. CEL & all.

BTW - I would get the BAT kit.

[DanN]

Thanks Greg..