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| Sturmovik |
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Theories are all well and good, but in reality GT40s will struggle to even reach 400hp with a 351W, letalone a 302W.
_________________ 1993 ED XR6 5speed Polynesian Green. Project car. |
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| ToranaGuy |
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{USERNAME} wrote: Theories are all well and good, but in reality GT40s will struggle to even reach 400hp with a 351W, letalone a 302W. What makes you say that dude? Cheers ToranaGuy
_________________ I am the ToranaGuy!|74 Lh Torana Turbo|78 Hz PanelVan|86 Mighty Boy Ute|93 EB2 Ghia,GT Mockup,5spd,LPGI,Full Leather|2 x EB Xr8 5spd's|{DESCRIPTION}|{DESCRIPTION}|{DESCRIPTION}| |
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| xafalcon |
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{USERNAME} wrote: {USERNAME} wrote: Theories are all well and good, but in reality GT40s will struggle to even reach 400hp with a 351W, letalone a 302W. What makes you say that dude? Cheers ToranaGuy +1 Engine displacement doesn't effect how much power is achievable from a fixed cylinder head flow figure, just the rpm at which that power is made. Larger engines will simply reach their power limitation lower in the rev range. The numerical calculation I submitted above is an approximation (based on well established industry formulas) and was primarily being used to demonstrate that 200rwkW should be (easily) acheivable with unported GT40P heads. In reality there are many other variables that effect the "exact" result such as induction restriction, camshaft selection, exhaust restriction, engine operating parameters (intake air temp, air density, engine temperature, oil viscosity, afr, ignition timing curve, compression ratio, fuel octane) etc. So, the formula can be used to get a reasonable idea of power output. It is very good to use when matching components in a combination. But the maximum flow figure calculation always assumes that the balance of the engine combination and operating conditions will also support the level of HP calculated. eg. using a small RV/towing cam will not allow the intake port flow to reach it's maximum, so this will reduce power output from that calculated.
_________________ XA Faimont 351C, AU2 XR8 Manual 5.0, DA LTD 5.0, Mk1 Capri 5.0, 1995 Mustang 5.0, EF2 XR8 Manual, EF2 Fairmont Ghia 5.0, AU3 XR8 Auto, AU2 XR8 Auto, AU2 XR8 Manual Ute, TE Cortina 5.0 Manual, DU LTD 5.0 soon to be manual |
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| xafalcon |
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{USERNAME} wrote: {USERNAME} wrote: snip You seem to be quite knowledgable on this xafalcon. If I was to expect about $500 for a CAPA tune, how much would I be looking at for labour for changing the cam out and installing 1.7 rockers? And with a warmish cam and a manual box I would be expecting about 190rwkw, yes? I already have the mods listed below aswell as a CAPA flash tuner box & 24lb injectors sitting in my garage. Trying to budget and hoard parts  Best you call a few places and get some quotes. Prices can vary considerably. Why don't you do it yourself, it's reasonably easy to do over a weekend.
_________________ XA Faimont 351C, AU2 XR8 Manual 5.0, DA LTD 5.0, Mk1 Capri 5.0, 1995 Mustang 5.0, EF2 XR8 Manual, EF2 Fairmont Ghia 5.0, AU3 XR8 Auto, AU2 XR8 Auto, AU2 XR8 Manual Ute, TE Cortina 5.0 Manual, DU LTD 5.0 soon to be manual |
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| XR9UTE |
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I agree with Vic......40p's are over rated.
By the time you port them and fit bigger valves you end up spending more money than aftermarket alloy heads which perform better already, are lighter, and don't have a funny plug angle that causes grief with headers. BTW 400hp has been achieved with the stock HO cam. |
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| EBXR8380 |
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Std flange plate can work fine...
_________________ As in ZOOM 126 edition |
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| xafalcon |
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{USERNAME} wrote: I agree with Vic......40p's are over rated. By the time you port them and fit bigger valves you end up spending more money than aftermarket alloy heads which perform better already, are lighter, and don't have a funny plug angle that causes grief with headers. BTW 400hp has been achieved with the stock HO cam. Saying that anything is "over rated" is subjective. It depends on what your basis for comparison is. In the case of GT40P's they fill a nice gap in windsor cylinder heads. Much better performance than stock E7TE's, and much cheaper than aftermarket. They are a very good performance upgrade for the price, with the potential to yeild a 20% increase in power for a basic bolt-on part. You are correct that if you add bigger valves and get them ported the overall cost is probably greater than the cost of some aftermarket heads. But nobody has said this should be done to reach the performance goal the original poster was targeting. The plug angle shouldn't cause problems. Run an Iridium plug and they don't need changing for 160,000k's.
_________________ XA Faimont 351C, AU2 XR8 Manual 5.0, DA LTD 5.0, Mk1 Capri 5.0, 1995 Mustang 5.0, EF2 XR8 Manual, EF2 Fairmont Ghia 5.0, AU3 XR8 Auto, AU2 XR8 Auto, AU2 XR8 Manual Ute, TE Cortina 5.0 Manual, DU LTD 5.0 soon to be manual |
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| XR9UTE |
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Well I gave the basis for the comparison....buying 40p's and expecting them to perform like an aftermarket head is wrong and in the end a waste of money as far as I'm concerned. As far as saying this should be done to reach the performance goal...I have said this should be done for the reasons I stated and the plug angle does cause problems. With some headers there may not be large problems but what would you rather have; problems or no problems?
If you are happy with the marginal performance increase from 40p's then ok, but usually(in fact everytime) I find that most people aren't and regret not going straight for the better option in the first place. |
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| xafalcon |
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A 20% increase in power potential is not a marginal increase. Any bolt-on upgrade delivering around 35-45kW for $500 is dirt cheap horsepower. Compared to an aftermarket head starting at around 3-4 times the price it's a no-brainer if the target horsepower is in the range supported by the GT40P head.
What is a waste of money is spending hard earned cash on over specced parts that aren't required to meet a performance goal. In this case aftermarket heads are not needed, and the extra $1000-$1500 they would have cost can be spent a lot more wisely in other areas. Not everybody wants an engine producing vast amounts of power, with a build cost to match. Many people just want an extra 70HP or so, and often have rather tight budgets to work within. The GT40P head fits nicely into these criteria.
_________________ XA Faimont 351C, AU2 XR8 Manual 5.0, DA LTD 5.0, Mk1 Capri 5.0, 1995 Mustang 5.0, EF2 XR8 Manual, EF2 Fairmont Ghia 5.0, AU3 XR8 Auto, AU2 XR8 Auto, AU2 XR8 Manual Ute, TE Cortina 5.0 Manual, DU LTD 5.0 soon to be manual |
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| ToranaGuy |
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If i keep my Xr8 & want to up the power, i'll be looking for Gt40p heads as a good budget upgrade, leaving some money for a better intake manifold, bigger TB and a cam as well. I'd rather not spend $2k just on the heads, then having nothing left to spend on other parts you need to change to make use of the expensive heads. If your only after the sort of power the OP is talking about, the GT40p's make better $$$ sense, than spending on heads that are probably too large for the target application.
Cheers ToranaGuy
_________________ I am the ToranaGuy!|74 Lh Torana Turbo|78 Hz PanelVan|86 Mighty Boy Ute|93 EB2 Ghia,GT Mockup,5spd,LPGI,Full Leather|2 x EB Xr8 5spd's|{DESCRIPTION}|{DESCRIPTION}|{DESCRIPTION}| |
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| nobbyxr8 |
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just to throw in what I`ve done over the last 10 years with my Fairmont Ghia 5.0l exstractors, 3" cat back explorer intake gt40p heads 70mm TB went alright but after driving my ba xr8 around it really shows that the old 302 needs alot to give it some poke like alot of the moden cars its not a nice feeling knowing a BA XT can give you a run for your money. in teh end I bit teh bullet and have starting building a dart block 347 then you get to the point where the engine is worth more than the car 7.5k and counting
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| EB-5LTR |
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i think another point to add, is the with g40p's you do not have alot of room to move for the future. Not only will alloys yeild you more power n/a over gt40ps but also offer way better potential in the future if you decide to go bigger cam, intake of forced induction route for street or strip use. Youl save money like this in the long run, instead of changing combos again.
Plus gt40p's are nearly 20kg heavier then alloys and come with crap valave springs + retainers which need upgrading with a cam (more money...may even need new valves etc....) and also have a thin deck height which isnt the best for boost. A gt40p, explorer, cam combo will only be on par with todays STOCK fpv/hsv range which isnt real flash (low 14 sec, high 13 sec??). I can also gareente that once you have done this you will want more power if its your daily or weekenders. Again if you only want around the 180-200rwk then gt40ps will suit. Cam is the key that makes the big difference in that combo if you decide to go down this route. Also stock e7's making 200rwk on an EFI? lol, there is no velocity in those heads.... Most i have ever seen e7's pull is 150rwk with cam, port work, exhaust, chip etc etc. unless its a set of E7 POWERHEADS |
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| ToranaGuy |
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E7 Powerheads?
Cheers ToranaGuy
_________________ I am the ToranaGuy!|74 Lh Torana Turbo|78 Hz PanelVan|86 Mighty Boy Ute|93 EB2 Ghia,GT Mockup,5spd,LPGI,Full Leather|2 x EB Xr8 5spd's|{DESCRIPTION}|{DESCRIPTION}|{DESCRIPTION}| |
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| EB-5LTR |
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http://www.powerheads.com/e7heads.html
inl exh .100 64 63 .200 123 110 .300 175 151 .400 204 170 .500 217 175 |
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| 67RCE |
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{USERNAME} wrote: A gt40p, explorer, cam combo will only be on par with todays STOCK fpv/hsv range which isnt real flash (low 14 sec, high 13 sec??). I can also gareente that once you have done this you will want more power if its your daily or weekenders. Again if you only want around the 180-200rwk then gt40ps will suit. Cam is the key that makes the big difference in that combo if you decide to go down this route. GT40P's aren't too bad. They are not the best head by far, but budget wise, they are a good option. My 185kw AU 1 XR8 ran an unopened, untuned 14.3@97mph with a catback and mechanical diff. I'd love to see what I can get with an exhaust + tune. To the OP, don't aim for power figures, aim for torque, and a 1/4 time. If you want a proven 200+rwkw setup, look at XH5LTWEPN's build. That will show what is needed to run a low 13 n/a AND have a very driveable car.
_________________ ILL60 - EF XR8, Sunroof, Ticky Kit, 19x8.5/19x11 TE37's, 347, AFr185's, TFS BoxRcustom converter, Hurst Quarterstick, huge billet cam. |
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