which one better for low comp 420 HP engine rebuild by SCS/Harvey Gibbs...?

 

The T38 is a miles better turbo than the surgemaster 240 pro

 

Neither a GT3071 is the better turbo.

Mark

 

shouldnt the tuner be specifying the turbo?

 

What he said just fitted a GT30,71 on my car and its awesome


Luciano

 

3071 all the way

 

Mark Shead from MADevelopment right..?, perhaps you don't remember me..but about 13 years ago I went to your workshop with my brother..when I was travelling to london at that time, how RU doin' mate..?

 

I would say Harvey is the best person to spec a turbo if he is building your engine.

Steve

 

Yes thats me doing very well.

Mark

 

is the GT3071 much more expensive than T38..and yes actually Harvey recommend me to use T38 SCS Spec, just reading some old post here and Simon S.E.C.S had good experience with MD240..so I need second opinion from you guys...

 

I know its better but you should be taking advice from your engine builder as then if you dont get what you want/expect its his fault,
Theres not much cost diff.

Mark

 

well..I'll talk to Harvey, he is a very open minded person from my previous communication with him..and Mark which turbo that you said "I know it's better " ?

 

The 3071 as the other 2 would not make it on my list.

Mark

 

after discussing with Harvey and read the dyno sheet comparison that he email to me, finally we decided to go with MD 240 SCS Spec..so it only gave 405 HP, but with very quick throttle response (boost came at 2250
RPM with 279.1 Lbs/Ft of torque@2500 RPM) Max Torque: 397Lbs/Ft@4000 RPM, Max Power: 405.1HP@6000 RPM ..less 20HP than the original plan with T38 though..but it'll be much fun to ride I supposed
now is the waiting game...
Thank's for your input mates..!

 

if you only wanted 400bhp...........then i'd of used a t34.......

 

he didnt he wanted 425 with the least lag...he lost 20 bhp but gained 500 rpm on a t34.63..nice little motor mate..cheers danny

 

Be interesting to see how a MD240 SCS varies from the usual shite that carries the MD240 label, as it sounds like you have got good results there, although personally I dont need to drive my car everywhere in 5th gear so would have preferred slightly later boost in the RPM from a GT3071 and it going miles better in the midrange and topend.

I can never see the appeal of focussing your tuning at sub 3Krpm on a vehicle fitted with a gearbox TBH!

 

indeed..Thank's Danny

 

.....no he didn't....the title says 420........but now he's going for 405.........so sorry to be fucking pedantic but a t34 will do that and be on FULL boost by 3400rpm.........

 

indeed..Thank's Danny

 

nobody said anything about full boost..hes already mapped it and its doing 400lb ft by 4k..yout34 will be circa 4400 rpm prob more..he has near nigh 300lb ft at 2250..your t34 will just be boosting by then...not the type of power id go for but if the bloke wanted 500 bhp he would of gone gt30..he didnt he wanted as much low down response as poss hence the way he and harvey went..fair play..cheers danny

 

actually the discussion I had with Harvey was exactly what you just explain Danny

 

yes i thought so as it was obviuos to me as harvey wouldnt of mentioned it..hes obviously got round the surging issues others have had too or he wouldnt bother using it...car will be very lively..cheers danny

 

Car will be very lively in situations like when you nail it at low rpm in a high gear on a motorway, much like a T3 car, but I bet its died on its arse at the high end of the rev range so I certainly wouldnt want it on a trackday toy etc.
So it depends what it is used for.
GT3071 does both jobs at once very well IMHO

Do you have a printout of the results for it off the dyno so we can see if im right about the torque curve dieing on its arse after about 6K?

 

of course the tourque curve will be gone after 6k chip as the peak power will be gone also..but alot of t34 cars are gone by then to..i wouldnt go gt30 unless i wanted circa 500 bhp...each to thier own..

 

The smaller GT30, the 3071, works really well at 450bhp or so on a YB, its that one I would go for.

 

mates...I lived in Jakarta - Indonesia, which is one of the most traffic jam city in the world..and we don't have much private road neither country road that you can really explore the maximum engine potential..that's why I was going this route to enjoy my ride optimally..before I was on GGR Stage 3 375HP which was more than enough power.

I even become national champion in european car race back then on 1997 with that engine, competing with highly tuned BMW, Mercedes, Alpha Romeo..etc. Anyway I really appreciated all of your concern.

And as requested this is a dyno sheet of the SCS Spec MD240

RPM LBS/FT BHP
2500 279.1 133.7
3000 357.4 204.5
3500 392.1 264.7
4000 397.0 303.4
4500 385.1 331.7
5000 384.4 366.2
5500 370.2 389.3
6000 353.3 405.1
6500 308.6 382.1
7000 290.4 386.6

 

Well the torque has certainly died off after 6K, under 300lbft by 7K, thats still not quite as bad as I expected though, so fair play to Harvey

 

Out of interest Chip do you know how much torque Rich's car makes at 7k ?

Steve

 

thats an awesom graph for an md240...tourque isnt an issue at those revs anyway and is only comparative to a 400 bhp engine....its not a 450+ bhp engine thats alot more laggy so has no comparison to this!!! danny

 

Its about 330lbft
So 15% or so more than on this MD240SCS, which to me is worth far more than it being more useful under 3Krpm, but im thinking in trackday car terms, as I mentioned earlier for a road car, it sounds like a great conversion that harvey has done.

If you go and look at rich's graph it looks like his takes far far longer to spool than this one, but thats massively exagerated by the fact that harvey is forcabley holding the engine back at each break point where as rich's was just allowed to rev naturally, so as a result rich's hasnt had a large amount of time to spool the turbo at low RPM like on the dyno figures in this thread.

Thats not me accusing Harvey of any wrong doing, MAD do EXACTLY the same thing when they dyno their engines on exacrly the same type of dyno, but rich's graph was done a rolling road which works differently as it takes all the values in one go, not plots out multiple held values.

 

Agreed. far better than ones I have seen in the past which are down to 250lbft or so by 7Krpm and normally surge their tits off in the midrange which prevents big boost.

 

definitely the most congested city i've ever seen!
macet banget! salam dari inggris