For those of you who haven\'t heard the full story:
I purchased a GT35/40 late last year, had it fitted to my 1995 Rex back in January and eventually had it mapped by Geff on CPL\'s rollers to run 14lbs in February. Car made 312 to the wheels on the stock motor and a rather suspect exhaust.
Unfortunately, the water seals perished shortly thereafter (car had already done 59,000 miles), so a rebuild was booked. Geff did a sterling job pulling out the motor and giving it a generous port. We also went for 1500 secondaries, a SX fpr (after the fse let us down) and a suitable manly mid-pipe.
Car was eventually mapped on Monday of this week back on Guy\'s dyno and ran to a magnificent 417rwhp! Maths isn\'t my strong point, but I think that equates to just under 510hp at the fly wheel. Car made this power on Optimax and at 0.8 bar. Simply put, it feels sensational!
I just want to take this opportunity to thank Geff and Chris, 20b_boy and Max Taylor for all their work on the car, enthusiasm and support. Cheers guys!
Joel
1 of 3
2 of 3
3 of 3
soon to be my new toy but will def be on show at trax on the fduk club stand for all to see(and hear joel u know what i mean)
Exceptional power :)
I personally couldnt live with the wastegate like that - prefer to shift by ear - totally impossible with the W/G barfing like that!! Then again I hate the blow off valve too where lots of people love them ;)
I\'m sad you\'re moving on Joel, you will be very much missed on a saturday - please dont be scared to bring the tonka toy down if/when u get it :D
All the best buddy,
PS Please, please Mr new owner - dont veilside this beauty! :(
Having been at CPL on monday, I\'d have to saythat this car really looked and sounded great.
To give you some idea of the noise - i had no idea where cpl was, but as i got close i could hear the car on one of its runs and it guided me in from about half a mile away!
Si
:rollin
Hi Si - were you the guy with the green car? sorry, didnt catch your name...
i spoke to geff about this car, and i must say i am most impressed, what a power increase from just rebuild and porting. Especially at 0.8 bar. Get it to 1.0 and take it to the strip you should whipp some serious ass.
well done geff.
regards
tony
Hi Ant
Have u spoken to geff since yesterday? only he had your LTX pludded into my FC last night - and it connected to the laptop and was running the 20b fine...
Hope u get it sorted soon mate,
That\'s really good power your getting! :eek:
Rich
Yeah mate, that was me - sorry, forgot to make introductions!
Si
luv to see the Dyno Chart, any piccies of that?
Superb power!!
Will pick the graph up next week, forgot it in our rush to get home before midnight!
omfg... what an awesome looking car! Not sold on the rear wing, but the "white with black bits" look is amazing; v.clean with the standard-ish lines
b :)
Hi Rich,
Spoke with geff, its winging its way back to me as i type so hopefully we will have it plugged in tomorrow and can see whats going on! How are your projects comming on? Must say though if could get over 400 bhp at 10 psi i would stick with the 13b as 20b uses soooo much fuel......
regards
tony
Something doesn\'t quite stack up here.
0.8 Bar implies a pressure ratio of 1.8 OR you have 1.8 times the torque at that boost that you would have had in a NA setup.
Taking the at the wheels figures (417 HP) this would mean a normally aspirated 232HP. Now for a street port that would be pretty good for flywheel HP, but no way would that be possible at the wheels.
So either the 417 is a corrected flywheel figure, in which case it is high, but not breaking the laws of physics, or that rolling road needs a good calibration, or your map sensor is wrong.
Or I have missed something.
Bill
or it could be a really good engine and turbo set up:D
Speak to Guy at CPL, he will confirm that it was reading wheel power and what boost was indicated by the dyno dynamics reading off the plenum. And I can confirm it was showing 0.8bar on both boost gauge and profec on the way home...
There were 4 or 5 other cars on the dyno that day, all gave very believable power and boost readings. And all witnessed by a few neutral onlookers...
Cant say more than that Bill, make of it what you want!
Ant; yeah - I posted the ecu today as Geff was busy on John\'s car and it was getting on :) Afraid they wouldnt guarantee nextday as its a saturday - you\'ll need to sign for it monday I think...it defoo works all ok tho.........
cheers rich, monday is fine.
regards
tony
I have never used CPL or seen their calibration certificate, but simple multiplication would indicate that those numbers are not possible at that boost without a full out race bridge port.
Hi all,
Sounds like a pretty impressive machine, so I\'m looking forward to seeing it at future meets:cool
and it looks stunning to boot!
Bill, You seem to have a great knowledge of mechanics and engineering from your other posts I have read since joining the club.
Is there a way to estimate what power is possible from the different kinds of porting? I guess this would then be multiplied by the pressure? how do you then account for the different sizes of turbos?? :confused: :confused: (damn I confused myself again.)
That would be a really interesting thread to post, for me at least as I don\'t really understand how everything works together.
Best way to really prove the power is to take it up the strip quite a few times and get a decent 1/4 mile time.
To give an idea of how readings vary we have had Gary Goodings at 461hp on the Dynohub(Hub reading)at 1.1 bar.That was a ported engine too on a GT 42/45 turbo,so well over 500hp flywheel.The rear wheel figure would have been around the same as the above figures for Joels car I think.Dyno sheet would be handy for Joels with the boost pressure reading on it and A/F\'s too,but all dynos can read quite variable figures,remember they are only a tool.
Boost pressure on Gary\'s is quite different to Joels.
I have also seen with my own eyes a reading of well over 550 rear wheel hp on an engine that I had built and we were tuning,but that was a fiddle by the rolling road guy just to show us how easy figures can be played with.Suffice it to say it is very easy.The real reading was considerably less.
Kind regards
Carl
I agree its high - but there was no reason for Guy to fudge it! I am merely giving the facts a sthose who were their saw them.
No one seemed interested in a dyno day for the tuners when it was mentioned recently; every one on the same dyno, same day etc would be as good as it could get for comparability.
None of the engine builders and/or tuners up for putting their setups on together. I\'m sure a few people would come along to see that!
Hi Rich,
I\'m not saying it was fudged but that people should not read so much into figures that\'s all.
It\'s like Danny has allways said "Pub Talk".
Prove it on the track.
Kind regards
Carl
Totally agreed; but lots of people just dont like going to the strip/or dont get to the strip often/at all (how many FDs ran at RS compared to how many were there?), and as experience counts for a lot - its easy to see how two cars of simliar power with differently talented/experienced drivers could run very different ETs/terminals e.g. half a second difference in the 60 foot that experienced launching might make...
The dyno is for tuning, the power run at the end is of little consequence in reality - just for the sake of the pub as you say Carl :)
All good fun :D
sounds like we need a dyno day. That\'ll shut up any arguments because they will all be done on the same day on the same dyno.
same fiddle can be applied to the dyno for all cars so they could all be over 1000bhp
Bring it on!!!
Geff
Up here then Geff? I\'ll happily arrange it [really need an evil smiley here] ;) :D and I\'m sure Bill wont have any problems with the figures :rollin
(http://www.computerpannen.com/cwm/contrib/ed/laughpf.gif)
got too say that that is an awesome power figure Joel.Well done to Geff and the boys. Just out of interest what are you goin for now? A porsche maybe.
Cheers Jay...:wave
QuoteOriginally posted by Carl
To give an idea of how readings vary we have had Gary Goodings at 461hp on the Dynohub(Hub reading)at 1.1 bar.That was a ported engine too on a GT 42/45 turbo
well lets do the same 1st order approximation on these numbers.
461HP at 1.1 bar equates to 209HP at no boost. A hub dyno removes a key variable so you only have diff and gearbox losses. These are quite low, but lets say 5%. This gives 220HP at the flywheel. Given the flow limitations of a turbo manifold and the loss of efficient exhaust scavenging, these numbers are high, but I could \'just\' about be persuaded that they were possible. The EBP would certainly be lower on a 42 turbine side compared to the 35/40 which is a fairly tiddly turbine.
Look at it another way. UK spec FDs were supposed to be 260FWHP. 230 at the wheels at 10PSI would be believable with a following wind and a well set up dyno. 461 at the wheels at the same boost would have a NA 13B putting out the same power as a stock turbo. Its just not going to happen.
QuoteOriginally posted by RE:Worx
sounds like we need a dyno day. That\'ll shut up any arguments because they will all be done on the same day on the same dyno.
same fiddle can be applied to the dyno for all cars so they could all be over 1000bhp
Bring it on!!!
Geff
Hi Geff!
About time you went on here for your self!
I can persuade the dyno guy to do a 1000 bhp run for you if you like.How much does it normally cost?
What boost would that be at?LOL
:rollin :D :rollin
Dyno graph would be nice to see though too,with boost curve.
On a more serious note though I think this coming Friday the 13th should be good!I hear that the Pod may see it\'s first road going RX7 put in a 10 second run with the aid of a few upgrades,like Nos!
Wish you and Tim all the best on your attempts.Get Joel to do some runs too!
Kind regards
Carl
;)
Would be nice to see the first rx7 do sub 12 on normal street legal tyres too. A rx7 doing sub 11 secs on street tyres would be awesome.
Bill,
Your calculations just seem to be based on boost? wouldnt air temp, degree of timing, fuel type/octane, all make a difference? rather than just deducting the amount of boost and coming up with a figure. If you force 1.1 bar of hot air into an engine you would need less advance. Only running 10 psi would mean the turbo is probably in its efficiency range, the air a LOT cooler and more advance could be run. Hence more power. Also, Joel might have a much better I/C and the fan at the R/road might be much more powerfull, all these would mean more power. Gurge\'s (GSB) car is running 340 odd BHP at 7 psi, 0.5 bar. At 0.8 he wouldnt be far off 417 bhp.
Also, if i remember correctly, Gary had a different gear box, this could use more power to turn the wheels. Joels gear box might be low mileage and in good nic, thus using less power. I dont think its a simple as just deducting boost and getting a N/A BHP figure, but then i\'m no expert, these are just my thoughts.
QuoteOriginally posted by antnicuk
Bill,
Your calculations just seem to be based on boost? wouldnt air temp, degree of timing, fuel type/octane, all make a difference? rather than just deducting the amount of boost and coming up with a figure. If you force 1.1 bar of hot air into an engine you would need less advance. Only running 10 psi would mean the turbo is probably in its efficiency range, the air a LOT cooler and more advance could be run. Hence more power. Also, Joel might have a much better I/C and the fan at the R/road might be much more powerfull, all these would mean more power. Gurge\'s (GSB) car is running 340 odd BHP at 7 psi, 0.5 bar. At 0.8 he wouldnt be far off 417 bhp.
Also, if i remember correctly, Gary had a different gear box, this could use more power to turn the wheels. Joels gear box might be low mileage and in good nic, thus using less power. I dont think its a simple as just deducting boost and getting a N/A BHP figure, but then i\'m no expert, these are just my thoughts.
Hi Ant,
Gurj\'s car is 347 at the flywheel though not rear wheel. So quite different from Joel\'s car. It seems a bit high for the boost but not unbelievable Royston had 348rwhp at 5800 rpm with a slipping clutch on a gt3540 at 13 psi so seems like his would of been roughly the same as Joels.
QuoteOriginally posted by Carl
I hear that the Pod may see it\'s first road going RX7 put in a 10 second run with the aid of a few upgrades,like Nos!
Is Tim hooking his NOS bottle back up then? ;)
Wish you and Tim all the best on your attempts.Get Joel to do some runs too!
Joel\'s car is sold - he wants a pickup truck!
QuoteOriginally posted by antnicuk
Bill,
Your calculations just seem to be based on boost? wouldnt air temp, degree of timing, fuel type/octane, all make a difference? rather than just deducting the amount of boost and coming up with a figure. If you force 1.1 bar of hot air into an engine you would need less advance. Only running 10 psi would mean the turbo is probably in its efficiency range, the air a LOT cooler and more advance could be run. Hence more power. Also, Joel might have a much better I/C and the fan at the R/road might be much more powerfull, all these would mean more power. Gurge\'s (GSB) car is running 340 odd BHP at 7 psi, 0.5 bar. At 0.8 he wouldnt be far off 417 bhp.
Also, if i remember correctly, Gary had a different gear box, this could use more power to turn the wheels. Joels gear box might be low mileage and in good nic, thus using less power. I dont think its a simple as just deducting boost and getting a N/A BHP figure, but then i\'m no expert, these are just my thoughts.
What I was quoting was a simple first order approximation, which is a useful engineering sense check. For a more accurate calculation you would need to take into account inlet temperatures and the reduction in density due to adiabatic heating within the compressor. Note that this would actually make the required zero boost HP HIGHER not lower.
The first order calculation assumed isothermal compression, so the boost was simply a torque multiplication off the normally aspirated figures. In other words a perfect turbo at 1 bar of boost will double the power of an engine compared to the no boost case. In this case it was enough to see that 417HP at 0.8 bar breaks fundamental laws of thermodynamics.
Rolling roads are tricky beasts. If a coastdown is not performed as part of the power run to give a corrected flywheel estimation, then the best you can hope for is that the curve shows you the best shift points.
Hi Rich,
I beleive that Tim has done a little on his car to improve it bit,but not Nos at the moment.
I also beleive that Geff has had his old turbo rebuilt and is now going to try Nos too.(Don\'t play games Rich)
Of course that may not be true but you would know more than anyone except Geff if that is the case.
Either way a 10 second run at last would be very good from either of them.
Bring it onas Geff would say!
Kind regards
Carl
QuoteOriginally posted by Carl
I believe that Tim has done a little on his car to improve it bit, but not Nos at the moment.
I think you\'re right, he suggested he would be fiddling in the mean time. I think he will be very close this time ;)
I also believe that Geff has had his old turbo rebuilt and is now going to try Nos too.(Don\'t play games Rich)
I think we all like to play games Carl - thats half the fun isnt it? :) Yep, old turbo rebuilt - I think the installation has changed some what though... He does have a NOS kit, but I dont think that will be used next time out, a couple of other things to try first and not enough time to get it hooked up in time I dont think :(
Of course that may not be true but...
...it keeps people interested which cant be a bad thing.
Either way a 10 second run at last would be very good from either of them.
Totally agree, lets hope some one cracks it - I imagine Ross will have a few new tricks up his sleeve upon his return from the land of the rising sun....
Are you going up at all? How\'s Garys getting on - I heard it was getting close now? I believe he has a trick crank of some sort - looking for some high rpm\'s eh? thats one thing geffs car lacks - the power high up the rpm range is very strong but you have to shift whilst your in the midst of it. Is Garys turbo a 42/45 or a /51 do you know out of interest? some of those babies look BIG!
See u soon,
Hello arguementative types:rollin :rollin :rollin ,
My car made 342bhp @ flywheel running 0.6bar boost on low boost setting as i had a leaking rad, now sorted with a new massive rad, also next week will be implementing larger injectors and a remap and possible air induction upgrade.
Will then a week later have it dyno\'d @ Thor engineering on the hubs not rolling road so should be more accurate, hopefully should be able to run @ 1.2bar???
Will post results when i get them a T78 should be good for over 500bhp, so we\'ll see what we\'ve got???
Gurj
That\'s in the same ball park as Gary\'s car, and again in the realms of \'possible\'. The isothermal envelope calculation puts this at 385 Flywheel at 0.8 bar. (Gary would be 380 at the same boost for the same assumptions)
So I have to conclude that with a street port you will be hard pushed to reach 400HP at the flywheel at 10PSI. So the car in question, whilst very possibly in the high 300\'s is not a 500HP car. I\'m sure with more boost it could be, but if it is/was being sold as having 500, then this incorrect.
just to update everybody i now own joels car and the rolling road figure was wrong due to various reasons car will be back to rolling road in the near future with new exhaust the present one came from concorde i suspect.once boost is adjusted i fully expect the car to produce in the region of 440-450fwhp and 360rwhp and will be happy to post any details requested.i will say even at 0.8 bar the car goes like a train and holds the boost all the way so at 1 bar shd be very impressive.i have replied to this to put record straight and am not claiming big hp figures to impress anyone only what i realistically expect from the engine.iam not a track junkie so wont be trying to prove its figures at all just intend to have a very fast road car
Hi Paul,
Thanks for setting the record straight on that.
I reckon you will certainly have a beast to be very proud when the final tuning is done.The car looks excellent and appears to have all of the right mods done to it.
Kind regards
Carl
Well thank you on bahalf of the laws of thermodynamics for clearing that up :-)
Are you able to share any information on why the reported figures were so badly out? As well as from interests sake there was little attempt to post a correction from people with a vested interest in this engine and its power output ( not yourself I hasten to add). In fact effectively there was a defense of the incorrect figures from those who ought to know better.
Had I not pulled people up on this I am sure that there would be forum members right now thinking that you could get impossible power numbers from an engine built by a certain company.
Could not have put that better, glad Im not the only one around here that see\'s a favourtism ( or poetic licence) towards a particular co.
congrates on the car, she is sweet and a good example, you will enjoy her.
my reason for posting this was not to level any criticism or blame as i stated the graph has only just become avail and there was no intention to mislead .joel posted the figures after a mobile phone call and never had a chance to discuss the figures before he posted in his excitement.while the figures were high it wasnt the only car being run that day so had limited time to investigate.and i add again the figures were posted by joel not the engine builder.once the exhaust has been changed for a more reasonable one car will be on the rollers and is fully expected to achieve approx 440-450fwhp and the approp rwp which will be very close to the previous figure.if everyone can be patient i will be present at the mapping in about a months time and will ensure the info posted is accurate.i understand there might be some underlying issues floating around here but having seen this happen on scoobynet it seems a shame to happen here after all bhp this and bhp that do not matter theyare just for chat between people and this really was a case of too much haste in posting the figures without having the data avail
so to sum up its a small community and more could be achieved if we all got allong
You have nothing to apologise for. However it remains that there are 2 people who should know better who should have pointed out that the posted figures were more than high, they were impossible. And both of them posted on this thread.
If the engine is well built I have no doubt that it will over time reach the required HP at around 1.1 to 1.2 bar
Bill
i understand there are certain issues here and would like to put this to bed now my car will be back for final mapping and i will only post what i blve to be accurate.i must stipulate again joel jumped the gun by posting the figure before any investigation had been done and it snowballed from there as human nature is to get defensive when questioned and i really dont think there was any intention to mislead and as with all things in life there are allways 2 sides to a story and i guess the lesson here was patience after all i should be the one saying but i thought it was 500bhp but i am not that bothered about a rolling road just how it goes on the road..anyway hope to see lots of u at trax and we can all compare rolling road printouts and have a laugh:rollin :rollin
Just got back and read this thread. Some of you guys should take more note of what Bill says. and also just look at the facts. 3540+street port+0.8bar=no where near 417atws.
Rich surely you realised it was too high.
I have never taken a car on the dyno, but guess the bride port is about 400 atws at the current 1.1 boost
QuoteOriginally posted by DRAGON
Just got back and read this thread. Some of you guys should take more note of what Bill says. and also just look at the facts. 3540+street port+0.8bar=no where near 417atws.
Rich surely you realised it was too high.
I have never taken a car on the dyno, but guess the bride port is about 400 atws at the current 1.1 boost
Hi Ross,
That is very reasonable for you to say. The bridgeport 13b makes around 250-280 flywheel N/A. Then add a little over twice the Bar(N/A +1.1bar),take a little out for air temp increase and you have probably just over 500 flywheel hp.A side port just could not make the N/A figures and so could never produce the same power at lower boost.
Kind regards
Carl