So ummn where is my wheelspin?
10-09-09, 07:37 PM
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So ummn where is my wheelspin?
So my cars finally making over 400whp (see thread https://www.rx7club.com/time-slips-dyno-128/chinese-t04z-power-844278/) but the thing is, i get no wheelspin. I thought i would get some when it came on boost or at least when i smashed the gears but it just chirps and goes. What the hell is going on? I have a cusco 2 way LSD in it with tein coilovers but the tires im running are 215/45/17
Should this be happening? I was doing 80km/h took took it to limiter and dropped the clutch into second and it just chirped and went. So does this mean im getting alot of traction, or my cars not really making 400hp? I was going to go to the strip tonight to see what it ran however its a major drag meet so i gotta wait till next weekend for the street meet. Has anyone else encountered this?
Should this be happening? I was doing 80km/h took took it to limiter and dropped the clutch into second and it just chirped and went. So does this mean im getting alot of traction, or my cars not really making 400hp? I was going to go to the strip tonight to see what it ran however its a major drag meet so i gotta wait till next weekend for the street meet. Has anyone else encountered this?
10-09-09, 08:05 PM
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Yeah im aware i should be happy without it. I see your getting an extra 140hp on me, were u getting much spin at around the 400 mark? Are you running a locked diff etc? When my car was on the stock turbo it wasn't chirping second very often now its chirping second and third so i guess thats a + lol
10-09-09, 08:07 PM
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Well it's just got me doubting the power my car is putting out, i was under the impression a 400hp fc would be hard to control. I mean they dyno sheet says it in black and white but oh well guess ill find out at the strip next weekend
10-09-09, 08:38 PM
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Well I havent purposely tried to do a burnout in the thing, waste of tires etc. And i only drove it back last night but 1 occasion I tried a slight launch ( was already rolling a bit) took it to about 5.5k in first dumped clutch floored it, shifted about 500rpm before limiter was a quick shift just slammed it in second and foot back to the floor, it didnt light up, it just chirped and kept going. Same with third didnt bother with 4th because i was already doing double the speed limit.
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10-09-09, 11:13 PM
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Well, you have a very laggy turbo and that is why you have such great traction.
Power comes on gradually and does not shock the tires into spinning and it takes a while to build back up after a shift so does not spin then either.
Your dyno chart is masking the character of your turbo because it is a 3rd gear pull from 4,200rpm to 8,000rpm.
Standard would be a 4th gear pull from 2-3,000rpm.
You are making just over 100hp at 4,200rpm whereas a well sized efficient single turbo making 400RWHP makes that same 100+hp at 3,000rpm and 200+hp at 4,000rpm.
At 5,000rpm you are making ~140hp and again well sized 400RWHP single would be at 260 to 310hp depending on full boost being run (12psi to 17psi boost).
At 6,000rpm you have 250hp and it looks like the turbo is getting spooled. Well matched 400RWHP turbo would be at 350 to 400hp at 6,000rpm.
At 7,000rpm you have 375hp, looks like you have hit peak boost and the powerband has started. Almost caught up to the 400hp a well matched single would have at this point.
At 8,000rpm they shut it down, but judging by the lower boost line below it power does not drop off hard after 8,000rpm.
Is this a 1.32 exhaust housing on the turbo?
Power comes on gradually and does not shock the tires into spinning and it takes a while to build back up after a shift so does not spin then either.
Your dyno chart is masking the character of your turbo because it is a 3rd gear pull from 4,200rpm to 8,000rpm.
Standard would be a 4th gear pull from 2-3,000rpm.
You are making just over 100hp at 4,200rpm whereas a well sized efficient single turbo making 400RWHP makes that same 100+hp at 3,000rpm and 200+hp at 4,000rpm.
At 5,000rpm you are making ~140hp and again well sized 400RWHP single would be at 260 to 310hp depending on full boost being run (12psi to 17psi boost).
At 6,000rpm you have 250hp and it looks like the turbo is getting spooled. Well matched 400RWHP turbo would be at 350 to 400hp at 6,000rpm.
At 7,000rpm you have 375hp, looks like you have hit peak boost and the powerband has started. Almost caught up to the 400hp a well matched single would have at this point.
At 8,000rpm they shut it down, but judging by the lower boost line below it power does not drop off hard after 8,000rpm.
Is this a 1.32 exhaust housing on the turbo?
10-09-09, 11:34 PM
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Well im hitting 3rd gear at about 120km/h maybe a tad more which is when its around the 200hp range, so i sorta see what you mean. Out of curiosity will this lack of wheelspin help with the 1/4 mile time, or will the power coming on so late cause it to run slower
10-09-09, 11:39 PM
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Yeah looking at that chart, im really going to benefit from making it rev harder. The thing is from 120 - 140 it pretty much doubles the HP thats coming out of it, so i'd think it would kick up some wheelspin there. But if i hold it right to limiter in second, ill be coming into alot more power then i would shifting earlier ill find out next weekend at the strip.
10-12-09, 05:12 AM
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I think I have at least solved this wheelspin problem. Not in a good way not gonna re upload the pics in this thread
https://www.rx7club.com/showthread.php?t=844278
https://www.rx7club.com/showthread.php?t=844278
10-12-09, 10:29 AM
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Referring to your dyno thread, there is a massive rich spot in your map just as the car comes onto boost. That certainly can't help with turbo response. It probably feels like the car has two powerbands.
10-12-09, 10:38 AM
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My car put down 425 RWHP and it hooks hard. Do you have the stock suspension? I do, and with the stock suspension travel it squats hard and weight transfers like a SOB. I do get a little wheel spin but considering the power to weight it's darn good.
Put some super stiff springs in with limited shock travel and you'll probably blow the tires off that thing
As others said wheel spin is just wasted power.
Put some super stiff springs in with limited shock travel and you'll probably blow the tires off that thing
As others said wheel spin is just wasted power.
10-13-09, 06:19 AM
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Yes i mentioned that rich spot, he spun some **** about making the transition smooth or something. In my dyno thread i took it to another shop today, the car made 313hp. And no i dont have the stock suspension as you can see by my sig. And yeah aaron the car feels like it has 2 power bands. This cars starting to wear me down with all these dramas on what should have been a simple turbo kit, i could sell it and get an FD but i think ill presist for a bit longer. Ive come too far to give up now
10-13-09, 06:35 AM
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My GTU spins all of 1st, 2nd and some of 3rd. Its very touchy. Hit the N.O.S. @ 100 and the *** end starts to spin out, but never does fully. Its f*&^ing insane!! It is the most stressful drive in the rain..
I put down 280hp with the hit and xtra fuel.
I run on Stock T2 rims/tires. LSD with custom solid rear diff and custom solid trans mounts. stock driveshaft with lube points. Custom drive shaft safety yoke.
Try a wastegate actuator line restrictor, I run 3 on my Turbo car, and its awesome with a 1500 rpm full boost!!
I put down 280hp with the hit and xtra fuel.
I run on Stock T2 rims/tires. LSD with custom solid rear diff and custom solid trans mounts. stock driveshaft with lube points. Custom drive shaft safety yoke.
Try a wastegate actuator line restrictor, I run 3 on my Turbo car, and its awesome with a 1500 rpm full boost!!
10-13-09, 07:11 AM
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My practically stock T2 nearly walked off the other side of the road(.. rear end first:Second 25 MPH roll) two days ago when i finally got it running; my dad was driving and he didn't use the clutch he just hit the the gas a bit. I'm guessing I need new tires.
10-13-09, 07:31 AM
#24
I have likely over 400whp here with 225 sumitomo tires right now. 1st is useless with more than 1/2 throttle, 2nd spins at WOT when it's colder out. I have a turbo and porting setup that is built for top end (4500-8000 rpm) so I think that makes the wheelspin more manageable than you would expect.
