TRW Pistons vs. JE SRP Pistons
- Thread starter ALBERTAN
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I believe the part number is SRP-139632 thats (.030)
Christian Dionne
Member
The JE rep told me the SRP's have a little higher silicon content than regular JE's. We somehow were "accidently" sent SRP's and didn't discover this until after we had $400 worth of Swaintech coatings on 'em. My buddy went ahead and used them in his soon to be 960hp twin turbo trans am. Let's hope they are indeed stronger than the real JE's.
TurboTony
Active member
SRP is the economy brand
I wouldn't call them the economy brand exactly. That sounds second rate/kmartish.
I would say the srp's are the slightly heavier/stronger brand of je's, thats more accurate. :wink:
I saw a pretty bad example of je strength this past race season. One piston crumbled in the 360 sprinter, couldn't explain it at the time, rod and cylinder looked good, wasn't rich or lean, didn't over rev, nothing.
Turns out the piston head was made too light and was oil canning at rpm. We figured this out after the engine builder had 6 other similar unexplainable failures. So now we are installing a heavier version of the same piston. Kinda sucks, requires a complete rebuild/rebalance after it was just repaired.
Whats the point to all this? Ultra light isn't always better. :grin:
TurboTony
I wouldn't call them the economy brand exactly. That sounds second rate/kmartish.
I would say the srp's are the slightly heavier/stronger brand of je's, thats more accurate. :wink:
I saw a pretty bad example of je strength this past race season. One piston crumbled in the 360 sprinter, couldn't explain it at the time, rod and cylinder looked good, wasn't rich or lean, didn't over rev, nothing.
Turns out the piston head was made too light and was oil canning at rpm. We figured this out after the engine builder had 6 other similar unexplainable failures. So now we are installing a heavier version of the same piston. Kinda sucks, requires a complete rebuild/rebalance after it was just repaired.
Whats the point to all this? Ultra light isn't always better. :grin:
TurboTony
Re: TRW Pistons vs. JE SRP Pistons
I realize this is an old post, but do these theories still hold water? I understand the SRP's aren't meant for huge boost now.....anybody? I discovered a few small hairline cracks on a couple of srp's and need to order a new set of pistons whether it be JE or SRP.....
thanks,
TurboTony said:
I realize this is an old post, but do these theories still hold water? I understand the SRP's aren't meant for huge boost now.....anybody? I discovered a few small hairline cracks on a couple of srp's and need to order a new set of pistons whether it be JE or SRP.....
thanks,
jwaller
Evil Genius/SyTy Guru
Re: TRW Pistons vs. JE SRP Pistons
you are correct the SRP isn't the best piston for us if you are going after a high boost(over25psi) build. I've had, ran, worked on 4 trucks that have all caved in the skirts on SRP's on high boost. if you call and talk with JE about them they will tell you the SRP we use is not meant for more than 13psi or so. but they are fine to 25ish. any more than that on a regular basis and they will cave in the skirts(esp if they see deto at that boost) over time and cause piston slap.
93ty475 said:
you are correct the SRP isn't the best piston for us if you are going after a high boost(over25psi) build. I've had, ran, worked on 4 trucks that have all caved in the skirts on SRP's on high boost. if you call and talk with JE about them they will tell you the SRP we use is not meant for more than 13psi or so. but they are fine to 25ish. any more than that on a regular basis and they will cave in the skirts(esp if they see deto at that boost) over time and cause piston slap.
Maxtor
New member
Re: TRW Pistons vs. JE SRP Pistons
I talked with a couple people recently about this Servando. It seems as though the advantage of the SRP's is with the higher silicon content when considering it for a daily driver. They may hold tolerances better, but I have also heard that the SRP's won't hold up under higher boost over a long period of time. Gerber may chime in here but he told me he just replaced a piston for the same issue Waller mentioned. FWIW, mine has regular JE's (not SRP's) in it, and has held 30psi several times with no issues.
I talked with a couple people recently about this Servando. It seems as though the advantage of the SRP's is with the higher silicon content when considering it for a daily driver. They may hold tolerances better, but I have also heard that the SRP's won't hold up under higher boost over a long period of time. Gerber may chime in here but he told me he just replaced a piston for the same issue Waller mentioned. FWIW, mine has regular JE's (not SRP's) in it, and has held 30psi several times with no issues.
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Re: TRW Pistons vs. JE SRP Pistons
here's some comparison pics of the old srp pistons vs. the new JE's....also included a couple pics of the cracked skirts...I removed the cracked piece in the last piston photo to show what exactly breaks....I didn't do any damage to the block...also, no rings were harmed during the breaking of the srp's :lol: ....also filled the bottom portion of the block with moroso block fill....
here's some comparison pics of the old srp pistons vs. the new JE's....also included a couple pics of the cracked skirts...I removed the cracked piece in the last piston photo to show what exactly breaks....I didn't do any damage to the block...also, no rings were harmed during the breaking of the srp's :lol: ....also filled the bottom portion of the block with moroso block fill....
sean
Member
Re: TRW Pistons vs. JE SRP Pistons
which piston is better between the trw, je, and srp. that can handle boost and be able to drive. also every body is talking about tolarance on the piston what does that mean? sorry for the dumd ? but i'm tring to get a real good piston for my build and teaching myself
which piston is better between the trw, je, and srp. that can handle boost and be able to drive. also every body is talking about tolarance on the piston what does that mean? sorry for the dumd ? but i'm tring to get a real good piston for my build and teaching myself
Re: TRW Pistons vs. JE SRP Pistons
I can't answer which is better, but I know I will be more careful my new JE's :lol: ....basically, the tolerance the difference you get when you measure the outide of the piston and then the inside of the cylinder...there's more to it than that, but you get the idea.....as far as the tolerance on mine, we ended up with .0065" piston to wall clearance and so far it's as quiet as can be....some said I might hear piston slap but I don't hear anything but air and injectors when this thing is cold....0065 is pretty loose but these JE's supposedly expand alot more than the rest when warmed up....
sean said:
I can't answer which is better, but I know I will be more careful my new JE's :lol: ....basically, the tolerance the difference you get when you measure the outide of the piston and then the inside of the cylinder...there's more to it than that, but you get the idea.....as far as the tolerance on mine, we ended up with .0065" piston to wall clearance and so far it's as quiet as can be....some said I might hear piston slap but I don't hear anything but air and injectors when this thing is cold....0065 is pretty loose but these JE's supposedly expand alot more than the rest when warmed up....
James Thomas
"NO CLASS"
Re: TRW Pistons vs. JE SRP Pistons
We have been using the Speed Pro #L2403NF slugs for about 3 years and have built 9 roots and centrifugal blown engines with them. They weigh an average of about 608 grams after clean up and pin fitting and come with dry film coated skirts out of the box. Don't know about anybody else but we have never damaged one and several of the engines have over 40,000 stop and go street miles with 18-22 psi. boost on a 144 c.i. blower. My personal engine has a 50 shot of N.O.S. on top of that.
We also are a Tech Line Coatings applicator and you would not believe how much difference properly applied performance coatings can make. We apply the barrier coating to the crown, oil shed to the under side and dry film the ring lands and pin bores. Just the pistons alone is worth roughly 8-10 on the dyno and several KR points. It gets a lot better as other parts are treated also crank, rods, intake and heads. Opps.... starting to sound like a for sale post. Sorry just sharing what works for us.
I can tell you that the immediate and brutal boost from damn near idle on a race prepped roots blower will destroy parts that survive a centrifugal blower even at the centrifugal's higher R.P.M. on the 4.3's. Roots is less than 0 lag at low R.P.M. and that's where high break effective cylinder pressures eat pistons and rods.The Speed Pro's have done well for us so far :tup: . We are doing another set tomorrow for my Ty's new build and I'll post up some pic's.
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James Thomas
sean said:
We have been using the Speed Pro #L2403NF slugs for about 3 years and have built 9 roots and centrifugal blown engines with them. They weigh an average of about 608 grams after clean up and pin fitting and come with dry film coated skirts out of the box. Don't know about anybody else but we have never damaged one and several of the engines have over 40,000 stop and go street miles with 18-22 psi. boost on a 144 c.i. blower. My personal engine has a 50 shot of N.O.S. on top of that.
We also are a Tech Line Coatings applicator and you would not believe how much difference properly applied performance coatings can make. We apply the barrier coating to the crown, oil shed to the under side and dry film the ring lands and pin bores. Just the pistons alone is worth roughly 8-10 on the dyno and several KR points. It gets a lot better as other parts are treated also crank, rods, intake and heads. Opps.... starting to sound like a for sale post. Sorry just sharing what works for us.
I can tell you that the immediate and brutal boost from damn near idle on a race prepped roots blower will destroy parts that survive a centrifugal blower even at the centrifugal's higher R.P.M. on the 4.3's. Roots is less than 0 lag at low R.P.M. and that's where high break effective cylinder pressures eat pistons and rods.The Speed Pro's have done well for us so far :tup: . We are doing another set tomorrow for my Ty's new build and I'll post up some pic's.
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James Thomas
93 TY 2185
Donating Member
Re: TRW Pistons vs. JE SRP Pistons
James let see those pictures of your Tech Line Coating on your TY pistons.
James let see those pictures of your Tech Line Coating on your TY pistons.